Rinse peas under cold water to separate. Drain. Heat oil in 12" skillet over med. high heat. Saute onion, garlic and parsley in oil. Stir in peas. Cook, uncovered, over med. heat 4 minutes. Stir in tomatoes, tuna, salt and pepper. Break up tomatoes . Cover and cook 20 min. or until fish flakes easily with fork.