Prepare the Marinade: In a mixing bowl, combine soy sauce, sesame oil, grated ginger, minced garlic, and wasabi paste (if using). Stir well to combine.
Marinate the Tuna: Add the Ahi tuna cubes to the marinade, ensuring they are well-coated. Let them marinate for at least 15 minutes at room temperature.
Coat with Sesame Seeds: After marination, remove the tuna cubes and sprinkle the sesame seeds on a plate. Gently roll the sides of each tuna cube in the sesame seeds until well coated.
Heat the Pan: In a large skillet or frying pan, heat the vegetable oil over medium-high heat until shimmering.
Sear the Tuna: Place the sesame-coated tuna cubes in the hot skillet. Sear each side for about 30-45 seconds to achieve a nice crust while keeping the center rare. Remove the cubes from the heat as soon as they are golden brown.
Serve: Arrange the sesame crusted Ahi tuna bites on a serving platter. Garnish with sliced green onions for a pop of color.
Notes
For a spicier kick, adjust the amount of wasabi paste to your liking.