As much fresh tuna as you plan to eat (sushi grade is this will be consumed raw)
Start out by cubing the tuna into whatever size pieces you like. I did about 1/4 – 1/2 inch pieces. Place your cubes in a bowl. Coat tuna cubes with just enough soy sauce to coat all of them. Don’t over do it. Add a few drizzles of sesame oil (this stuff is strong) to taste. Mix up everything. Next up add a dab of the oyster sauce – this is to add a bit of sweetness and thicken up the soy sauce mix again. Cover the tuna and put in the fridge to marinade for about an hour.
Prepare some white rice. Top the rice with the tuna mixture and add green onions for color and flavor. Garnish with sesame seeds and enjoy!