Note: as of 11/20/23, the most helpful answer in regards to the core question here was posted in the comments section by that prolific author "anonymous" 😀 who, to paraphrase, states that the quality of the taste of sushi would be significantly lowered if the the fish were not bled out, so that it is standard practice to drain out the blood. Consequently, fish are always bled out. Ergo, it would seem that we can eat Sushi without fear of violating the Noahic Covenant and the Apostolic Councils' decree.
However, James makes clear there are certain transcendent principles wrapped up in the Torah that Gentiles need to be aware of and obey (v. 20): clearly, anything thats smacks of idolatry or immorality (porneia, all immoral sin, not just adultery--what a counter-cultural thought in the 1st century!) need to be avoided. He also, however, mentions "things strangled," and "blood." [It's worth noting that there are a variety of interpretations regarding the significance of these 4 prohibitions being lumped together; no time to get into that today! I will mention, however, that all are probably closely linked to pagan idolatry, though David Instone-Brewer has made an intriguing case that "pniktos" refers to infanticide via "smothering" rather than strangling; you can read his article here] In my opinion, the prohibition of blood is a transcendent principle, since it goes all the way back to the Noahic commands in Genesis 9:1-7, given before Abraham was ever born.
Now, fortunately, the red juice in a "medium rare" steak or burger is apparently not blood (see this article). However. blood sausage and other dishes that actually contain blood are out of the question for Gentile (and Jewish) Christians. Once again, this prohibition against eating blood (which I assume is what James means by "blood" in v. 20) has existed from the very beginnings of when the Lord allowed humanity to eat meat. I do not deny that "blood" in Acts 15 is linked to pagan idolatry (though that was not the context in Genesis 9), but this does not mitigate the broader principle any more than "fornication" (porneia) in the same context would be limited strictly to cultic prostitution or other idolatry-linked immorality.
However, one of my NT Intro seminary students, James, raised an interesting question: what about sushi? Technically, fish has blood, and technically, the blood is not drained in real sushi (from what I understand). Does this mean that raw fish, as generally prepared, is prohibited for all Christians, Gentile and Jewish?
I honestly don't know the answer to this. From the modern Jewish perspective, apparently raw fish is ok, as this Rabbi states (with thanks to another of my students, Alonso, for sharing this link). This is addressed in Jewish commentary here (from what I understand). However, whether or not this would represent a biblical (as opposed to traditional) reading, I don't know.
Once again, I see no way of getting around a full prohibition of intentionally eating blood at least in regards to land animals, so blood sausage, etc. is out. Nor does the prohibition apply strictly to when it's linked to pagan idolatry, in my opinion, in light of the fact that it originates with the Noahic Covenant. So, there is one huge issue that needs to be grappled with:
What constitutes a biblical definition of "blood"??
In other words, would Moses (under the inspiration of the Holy Spirit) and his original audience naturally think of "fish" when writing the words of Genesis 9:3-4?
There's a hint in the Torah itself that he may not have been thinking of fish. In Leviticus 7:26, the prohibition against blood is apparently clarified by the preposition l attached to two nouns: "ōph" ("bird") and buhēmah ("beast"). The word for "fish" (dagah) does not occur here (though that is actually a rare word), nor do we see any of the key terminology describing "fish" from, e.g., Leviticus 11:9. So although in a modern scientific sense fish have "blood," as far as Moses is concerned it's not close enough to count.
Unfortunately, being a New Testament specialist rather than an OT guy, I'm totally out of my depth here (pun not intended!). I can only conclude with four thoughts:
1. We Gentiles are not under the Torah (i.e., the body of Laws meant specifically for Israel), and thus we can enjoy our barbecue pork (so long as we do not cause our brother or sister to stumble).
2. However, the Torah is still applicable to us and is meant for our instruction (for one of the better discussions on this, see William Combs' article in the Detroit Baptist Seminary Journal here).
3. There are, however, transcendent principles going back to the pre-Abraham era that still apply to us, especially when reiterated at the Apostolic Council of Acts 15. This includes the prohibition against eating blood (all meat that we eat should have been subjected to a reasonable effort to remove the blood).
4. Whether or not sushi would fall under that prohibition is, in my opinion, still an open question and needs to be addressed by an Old Testament scholar (to my knowledge none have done so yet; please point me in the right direction of I'm wrong!)
With thanks to my seminary students Alonso and James for their dialogue on this, as well as my friend Alex in North Carolina!