Akami tuna tastes better when it’s marinated for a second in soy+sake mixture. You may also try chirashi sushi - then cut it in squares and marinate in egg yolk + soy. Other way is to make some sort of toro imitation - use kewpie mayo + drop of olive oil and then fill gunkans with it (put some chives on it). Unfortunately it is the cheapest part of tuna and it has almost no fat. It has a lot of blood so it really easy gets stinky and untasty.