Tuna Empanada Filling

Name: Tuna Empanada Filling
Ingredients: 3 tablespoons olive oil; 1 medium onion (finely chopped); 1 cup red bell pepper (capsicum, about 1/2 to 2/3 of pepper, chopped); 1/2 cup green bell pepper (capsicum, about 1/2 pepper, chopped); 1/2 teaspoon salt; 5 cloves of garlic (diced); 1/3 serrano chili (or jalapeño, red or green, diced); 1 roasted red pepper (diced (canned like these)); 10 green olives (diced); 1.5 teaspoons paprika powder; 1 cup tomato passata (chopped tinned tomatoes); 14 oz. canned tuna (drained weight (400 g)); Garnish: sliced roasted red peppers (olives and green onions)