Play around with the quantities depending on your own tastes.
Chop the tomatoes, chillies, onion and coriander finely. Feel free to also chop the coriander stalks as they pack a lot of flavor. You can deseed the chillies if you want, I personally don't bother.
TIP: Start by chopping the tomatoes to determine the amount of salsa you will end up with and how much onion, chillies and coriander you will need. I strongly recommend adding plenty of coriander.
Mix all ingredients and Add a good pinch of salt and a few drops of lime, you don't want the lime to overpower just a few drops to sharpen the flavors.
IMPORTANT: let the salsa rest for at least 20 minutes to allow the flavors to develop and then check for seasoning again.
Enjoy with corn chips, tacos, quesadillas, tostadas... You name it.