Spanish Tuna Stuffed Sweet Potatoes

Name: Spanish Tuna Stuffed Sweet Potatoes
Ingredients: 4 medium to large sweet potatoes (with skin on); 2 tablespoons olive oil; 1/2 teaspoon sea salt; A generous pinch of pepper; 3 tablespoons olive oil; 1 medium onion (finely chopped); 1 cup red bell pepper (capsicum, chopped (1/2 to 2/3 of pepper)); 1/2 cup green bell pepper (capsicum, chopped (1/2 pepper)); 1/2 teaspoon salt; 5 cloves of garlic (diced); 1/3 serrano chili (or jalapeño, red or green, diced); 1 roasted red pepper (canned, diced); 10 green olives (diced); 1.5 teaspoons paprika powder; 1 cup tomato passata (chopped tinned tomatoes); 400 g canned tuna (drained weight); Garnish: sliced roasted red peppers (olives and green onions)