Use fresh sushi-grade tuna steaks, about a half pound per serving - This recipe assumes about 3 portions.
1/2 cup soy sauce
About 1/2 cup sesame seeds
1 tablespoon sesame oil
1/4 cup Teriyaki sauce
1/4 cup soy sauce
1/4 cup sake and/or Mirin (rice wine)
1/2 cup finely chopped green onions
In a shallow dish, large enough for all the tuna to lie flat, splash tuna with soy sauce and sesame oil. Use no more than about a tablespoon of sesame oil, as it has a very strong flavor. Turn steaks over to coat.
Meanwhile, toast the sesame seeds in a dry sauté pan over medium high heat, shaking and tossing until they start to brown, then remove from heat and set aside.
Prepare side dishes, sauce, rice etc.
In a medium sauté pan or skillet, heat peanut oil until it smokes. Using tongs, (a fork will tear the tuna) sear the tuna one piece at a time - maybe a half a minute on each side. It will cook very fast, so be quick. It’s supposed to be quite raw on the inside and only about an 1/8 inch done on the outside.
Remove fish to a cutting surface and using a very sharp knife, cut into strips, arrange on platter and sprinkle with the reserved sesame seeds.
Serve with Ponzu sauce.