Drizzle sesame oil over tuna. Combine soy sauce, grated ginger, sugar and black pepper into a small bowl. Pour mixture over tuna. Place sesame seeds on a plate and mix. Press tuna steaks unto sesame seeds on all side and set aside.
Heat a cast iron pan over medium heat. Add a splash of olive oil to the pan then sear tuna steaks about 1 minute per side. Don't forget to cook the sides as well.
Combine the sauce ingredients in a small saucepan and let it boil on low until thickened.
Serve tuna with your favorite salad and sauce.
Recipe by The Gluten Free at https://www.theglutenfree.com/gluten-free-sesame-crusted-tuna/