Preheat oven to 375 degrees F
Combine Salt, Pepper, Garlic and pepper flakes together thoroughly and rub on both sides of tuna steaks.
Place 2 tablespoons of olive oil in shallow baking dish and lay in tuna steaks
Combine remaining 6 tablespoons olive oil, lemon juice, and teriyaki sauce and pour over fish. Bake for 30 minutes or until fish flakes easily with a fork. Baste with seasoned oil mixture 2 or 3 times during baking.