Here is my favorite - very easy.
 
 Cilantro Lime Salsa Fresca
 
 3 large tomatoes or 5-6 plum tomatoes, diced small
 1 med. white onion, diced small
 1 jalapeno or other hot pepper, diced (you decide if you want to seed it 
 or not ;) 
 
 juice of 2 limes, or one lemon and one lime
 1/2 cup chopped fresh cilantro
 salt to taste (I like alot, but if you're watching your sodium...)
 
 
 Combine everything in a bowl.  Cover and refrigerate a couple of hours or 
 overnight before serving.