Wash and pat dry tuna. Coat in a layer of soy sauce. Add sesame seeds to a shallow bowl in an even layer. Coat all sides of the tuna.
Get a skillet ripping hot and turn on fan as it will get a little smoky (don’t worry, it’s quick). Once oil is hot, add tuna and let sear for 1-3 min (depending on how thick your steak is). Flip and repeat on other side.
Remove and slice into strips. Make cucumber salad by combining all ingredients in a bowl and mixing well until combined. Serve with sushi rice and any other fixings you like! Enjoy!