Dice tomatoes and onion into small chunks and add to a medium bowl.
Remove the stem from the jalapeno. Cut the pepper in half and remove the seeds and ribs with a spoon. Dice the remaining parts of the pepper very small and add the bowl.
Chop the cilantro well and add it to the bowl as well.
Juice both limes into the bowl, add the salt and stir thoroughly.
You can serve immediately or let the flavors meld a bit in the fridge first. I like it either way.