Sort of like a guacamole dressed up - pico de gallo! It's delicious and can be done ahead by squeezing some lemon juice over the top to keep it from browning.
2 avocados, diced
1 tablespoon vegetable oil
1 clove garlic, minced
1 cup diced onion
cilantro to taste
6 tomatoes, seeded and diced
Salt, pepper
Just mix everything together. Serve with tortilla chips.