I grew up eating the many ethnic foods available here in Hawaii, including the local versions of nori
maki and inari sushi. The first time I ate tekka maki and onigiri sushi was in Japan. I am far from a being a sushi chef, but make passable sushi.
Prepared wasabi in plastic squeeze tubes imported from Japan is readily available. In the past everyone in Hawaii used karashi (yellow mustard, the kind served with oden and gyoza). There are a few people here that grow wasabi which does best grown next to cold, clear spring water.
Yellowfin tuna in Hawaii is called ahi. The Japanese call big eye tuna maguro and tend to use the term for tuna.