This is a local appetizer dish made & served here in my home state of Hawaii. it can be made many many different ways. But this is a simple easy & yummy way to make it. I make it just about once or twice a month when I make fried fish & or what I call my lualua night. Also here in Hawaii we call Blue Fin Tuna by it's Hawaiian name "Ahi"
1st in a small bowl mix little bit of the wasabi & soy sauce. Taste to make sure its not to hot. Set aside.
Then slice & chop the raw fish aka Sashimi into bite size pieces. place in a medium size bowl. Lightly toss with the salt.
Then lightly drizzle over the soy sauce mixture. Mix gently & taste to make sure once again its not to spicy.
Place in ice box and let all the sauce & fish come together. Enjoy by itself as a "Pupu" as we would say here in Hawaii or appetizers on the mainland. Just before serving sprinkle the green onions over.
Note" Goes good with a bowl of hot fresh white rice, any kind of Local Hawaiian food or lualua as we would say.