I'm a little late for Cinco De Mayo, but I was watching a TV cooking show, Mexico - One Plate at a Time, hosted by Rick Bayless.
He demonstrated a super simple salsa that require no cooking, just cutting up some veggies and using a food processor or blender. Also, the salsa looked delicious too.
Reference: Recipe from Season 7 of Mexico - One Plate at a Time
Link: Crunchy Tomatillo-Avocado Salsa
Salsa Verde Crujiente con Aguacate
Makes about 2 1/2 cups
8 ounces (about 4 medium) tomatillos, husked and rinsed
1/2 cup (loosely packed) coarsely chopped cilantro
Hot green chiles to taste (roughly 2 small serranos or 1 small jalapeño), stemmed and roughly chopped [I used two roasted pepper - 1 serrano and 1 jalapeno]
1 ripe avocado, pitted, flesh scooped from the skin
1 small white onion, cut into 1/4-inch pieces
1/4 C water so the blender/food processor can create a puree.
1) Combine the water, cilantro, half of the tomatillo - coarse chopped and half of the avocado. Process into a coarse mixture.
2) Chop the onion and rinse through a strainer. This will take some of the bite off the onion.
Chop the remaining tomatillo and avocado - about 1/4" dice.
3) Pour into a bowl and combine. Add salt to taste.
4) Cover and refrigerate until needed.
A nice slightly tart green salsa that's very simple to make. The salsa gives a refreshing brightness to a dish.
I think a clove of garlic would be a nice addition too.