1In small bowl, mix together soy sauce, sesame oil and chili sauce.
Place tuna on a plate and pour sauce evenly over tuna, turning to coat all sides. Leave the tuna on the counter to come to room temperature for one hour, turning tuna several times in marinade.
2Heat a non-stick (or well seasoned) pan over medium high heat until very hot, add 1 tablespoon extra virgin olive oil to pan and swirl to coat evenly (or use non-stick cooking spray). Place tuna steaks in pan and cook for 2 minutes, flip and cook for 2 minutes more.
3Remove to cutting board and slice across the grain in thin slices. Serve with wasabi or soy sauce.