Wash the tomatoes and chiles.

Dice the tomatoes into small cubes and place them in a bowl to add the other ingredients later.

Chop the onion and add it to the tomatoes, then mix.

Remove the veins from the chiles, chop them, and add them to the mixture.

Wash the cilantro, chop it, and add it to the mixture.

Finally, add a bit of salt for more flavor, and it's ready.