Cook sushi rice according to packet instructions. Allow to cool once cooked.
Using an egg ring, tightly pack in your cooked sushi rice forming a layer approximately 2cm in height. Repeat until you have formed 8 buns.
Heat oil in a flat frying pan over medium-high heat. Once the pan is hot, add your sushi buns, being careful not to overcrowd the pan. Cook for 4-5 minutes until golden brown and crispy. Flip carefully and cook on the other side for another 4-5 minutes. When removing from the pan be careful not to stack them on top of each other as they may stick.
Cook your steaks for 2-3 minutes on each side, basting with extra teriyaki sauce.
Assemble your burgers with one bun, a slice of lettuce, steak, Kewpie mayo and top with the second bun and any additional toppings such as furikake (a Japanese rice seasoning) or pickled ginger.