Add all ingredients into a large bowl, and stir to combine.
Adjust the lime, salt and pepper (if using) to suit your taste.
Serve immediately, or refrigerate for up to a few hours. Best served the day you make it.
Tips:To take the "bite" out of the raw onions, add them to a bowl of water with ice cubes, and let them sit for about 10 minutes, then drain before combining with the other ingredients. Salt will draw the moisture out of the pico de gallo, so you may find that your pico de gallo is very watery after you take it out of the fridge. You can just drain the mixture and re-adjust the seasoning before serving. Please note that the nutritional information for this recipe is only an estimate, and has been calculated using a plugin.