Wash and roughly chop Roma Tomatoes. Place in a food processor (or blender) and pulse until the texture is how you like it. (I like mine slightly chunky). Place in a bowl.
Add salt into tomato mixture. (Salt helps draw water out of the mixture.) Drain excess water.
Dice yellow onion. Add to tomatoes.
Finely chop Jalapeno. You can add as little or as much as you'd like. Add to the onion - tomato mixture.
Add more salt and pepper to your liking.