Ensalada Chilena (Chilean Salad)

Name: Ensalada Chilena (Chilean Salad)
Cuisine: Mexican, Latin American, American
Ingredients: 4 large ripe tomatoes; 1 medium white onion; 2 tablespoons fresh cilantro, finely chopped; 2 tablespoons olive oil; 1 tablespoon fresh lime juice (or lemon juice); ½ teaspoon salt (adjust to taste); ¼ teaspoon freshly ground black pepper; Optional A dash of red chili flakes for heat