Cut the tomatoes into halves. Scoop out and discard the pulp and seeds. Cut the flesh into 1/4-inch cubes.
Peel the onion and chop into pieces roughly the same size as the tomatoes. Optionally, dump into a bowl of iced water for 10 minutes to remove the sharpness then drain well.
Split the habanero lengthwise. For less heat in your pico de gallo, scoop out and discard the seeds before chopping the habanero finely.
Finely chop the cilantro leaves.
Place the prepared tomatoes, onion, habanero and cilantro in a bowl, and toss lightly.
Zest the limes and add as much or as little to the vegetables.
Cut the limes and squeeze the juice of one lime directly over the vegetables.
Sprinkle in salt.
Toss the pico de gallo and taste. Taste, add more salt and / or lime juice and toss until you get the balance of flavor that you prefer.