There are few things as simple and delicious as this salsa.
It works well with many Mexican dishes, adding a bright, spicy freshness. It tastes great on tostadas, tacos and as a topping for scrambled eggs and molletes (Mexican bean and cheese sandwiches).
Below is my version, which is pretty traditional, but you can vary the amount of each ingredient to your taste.
Pico de Gallo (Fresh Tomato Salsa)
3 – 4 Roma (plum) tomatoes, cored and diced
1/2 cup white onion, finely chopped
2 serrano chiles, stemmed, seeded and finely chopped
1/3 – 1/2 cup cilantro, chopped
1/2 lime, juiced
salt to taste
Combine all the ingredients in a bowl and mix. Cover and let it sit for 5 – 10 minutes in the refrigerator. Serve as a topping or along with chips as an appetizer.
Make sure to use the pico de gallo soon after you make it. I often have the tomato, onion and chile ready in a bowl and add the cilantro, lime juice and salt right before I need it.
el chino latino cocina 
This pico looks great!
Love pico!!