1. In medium saucepan, combine half cup olive oil with parsley, red peppers, sca llions, 2 tablespoon. lemon juice, capers, oregano, and salt. Simmer over low heat 5 minutes, stirring occasionally, to blend flavors. Remove from heat and set asi de.
2. Place tuna in a single layer in a glass baking dish. Drizzle remaining quarter c up olive oil and 2 tablespoon. lemon juice over fish. Season with pepper. Turn to coa t both sides. Cover with plastic wrap and marinate at room temperature 30 minut es.
3. Prepare a hot fire. Place fish on an oiled grill set 4 to 15 cm from coal s. Reheat sauce by placing saucepan on side of grill. Grill tuna, turning once, until opaque throughout but still moist, about 8 to 10 minutes. Transfer to a serving plate and spoon sauce over each steak.