Add all the ingredients to a medium bowl, and toss to combine. Cover and chill until ready to serve. Add more salt if needed for taste.
Deseed your serrano chile or jalapeno pepper, especially if you don't like a lot of heat. Traditional Pico de Gallo is made with serrano chiles but if you want something less spicy then go with the jalapenos.
Serve right away or refrigerate if you like for 2 hours then serve. Store leftovers in an airtight jar or container in the refrigerator for up to 5 days. This recipe makes 3 cups of salsa.