1. In medium saucepan, combine 1/2 cup olive oil with parsley, red peppers, scallions, 2 tbsp. Lemon juice, capers, oregano, and salt. Simmer over low heat 5 minutes, stirring occasionally, to blend flavors. Remove from heat and set aside. 2. Place tuna in a single layer in a glass baking dish. Drizzle remaining 1/4 cup olive oil and 2 tbsp. Lemon juice over fish. Season with pepper. Turn to coat both sides. Cover with plastic wrap and marinate at room temperature 30 minutes. 3. Prepare a hot fire. Place fish on an oiled grill set 4 to 6 inches from coals. 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.