Prepare the Base: In a medium serving bowl, combine the chopped onion, jalapeño, lime juice, and salt. Let it marinate for about 5 minutes while you prepare the other ingredients.
Chop Additional Ingredients: If using, dice the avocado, mango or pineapple, mince the garlic, and dice the red bell pepper.
Add Tomatoes and Cilantro: Add the chopped tomatoes and cilantro to the bowl. Stir to combine.
Incorporate Optional Ingredients: Gently fold in the avocado, mango or pineapple, garlic, and red bell pepper, if using. Sprinkle ground cumin and drizzle olive oil over the mixture if desired.
Season and Rest: Taste the mixture, and adjust with more salt or lime juice if needed. For the best flavor, let the mixture marinate for at least 15 minutes or several hours in the refrigerator. This allows the flavors to meld together nicely.
Serve: Serve the Pico de Gallo as a dip with tortilla chips, or use a slotted spoon or large serving fork for serving with tacos, grilled meats, or fish to avoid too much liquid.
Storage: Store any leftover Pico de Gallo in a covered container in the refrigerator for up to 4 days. Note that the added fruits (if used) will soften over time.
