Chop all your ingredients: Chop your tomatoes into large chunks (if you're using grape tomatoes or cherry tomatoes, you can skip this step), then chop your onion into slightly smaller chunks (about half the size of the tomato pieces), and then chop your garlic and peppers pretty finely.
If you're using a food processor (you can also just use a knife), transfer your ingredients there now. Do not push the on button and just let it blend - this will give you spicy juice instead of a nice, chunky salsa. Instead, pulse your food processor in roughly 50 super quick bursts that last a fraction of a second each.
If you are using a knife instead of a food processor, first make sure your knife is really sharp so your vegetables will retain their liquid. Mince your garlic as finely as you can, and chop your peppers very small. Then dice your onions and tomatoes small but bigger than the peppers. Transfer to a bowl, add your salt, and mix thoroughly.
Taste and adjust as needed, noting that both the saltiness and spiciness will decrease some after the flavors meld together. If you need to add something at this point, stir it in instead of using the food processor so that you don't break down the texture of the pico de gallo.
Serve and enjoy!