Quarter the onion and place in the blender.
Quarter the jalapenos and place in blender.
Place as many seeds as you wish for heat.
I use a lot.
You can add the lime juice now.
Chop up in blender (or food processor).
Remove and put into a bowl large enough to hold the tomatoes.
Core and quarter the tomatoes, add salt and place in blender and chop.
Add this to the salsa and taste to adjust any salt, lime juice or more seeds for heat.