I was surprised to find rather few threads on grilling tuna steaks, so I'll add to the number here. In this case, my local fishmonger has lots of "sashimi-grade" small steaks (yellowfin). Important point: they're small--about 4-5 ounces each and not more than 3/4 inch thick. I bought three to do some test-cooking.
The thinness leaves little room for the seared-outside-and-raw-inside approach, for which I have limited affection, in any case. Approaches I've considered:
1. A 1998 Cooks Illustrated method involves soaking the steaks in just olive oil for an hour at least, which allows the fish to hang on to moistness better, even done to medium.
2. I'd like to revisit a sweet Asian-style marinade approach, but my efforts in the past have been merely okay. I've found that my marinade is a bit runny, so the fish is not richly colored or flavored at the time I have to remove it to avoid overcooking.
Thanks in advance for any tips.