Recipe source.

Ingredients

• 4 large plum tomatoes (~1 pound), diced (should yield about 2 cups)
• 1 small white onion, chopped (should be about 1/4 cup)
• 3 tablespoons chopped fresh cilantro leaves (can use dried but won't be as tasty)
• Pinch or two of coarse salt
• Juice of one lime

Steps

1. Combine all the ingredients in a bowl.
2. If you prefer a smoother texture pulse half the salsa in a food processor, then combine it with the remaining chunky half. This is optional. 
3. Cover tightly and refrigerate for up to 5 days.