Marinate tuna for 30 minutes, coat with with sesame seeds, sear, and serve with spicy wasabi sauce.
The trick to getting sesame seeds to stick is to have a gentle hand. Lightly dredge them in the sesame seeds by patting down. Don't try to manhandle or harshly roll them around the sesame seeds. If there are bare spots on the tuna, then sprinkle a couple more sesame seeds on the tuna slices.
Find it online: https://eatsimplefood.com/sesame-tuna/