Pico de gallo is a Mexican condiment, a type of salsa cruda made from onions, chiles, tomatoes, lime juice and cilantro. This salsa would be served with tacos or beans or meat and poultry dishes. The name translates literally to "beak of the rooster".
Combine the first four ingredients in a medium bowl. Squeeze the lime over the chopped vegetables, sprinkle with a pinch or two of salt and fold gently to combine. Taste the mixture and adjust the salt if needed. Serve immediately.