This recipe was borrowed from my friend Tamara over five years ago, and I make it for all of my parties. I just eyeball the quantities to my tastes, so what you see below are estimates.

Ingredients: 
2 ripe but firm avocados, diced
1/4 a large red onion, diced
2 tomatoes, diced
1/3 can small white beans
1/4 cup cilantro, finely chopped
juice of 1/2 lime
salt and pepper to taste

Mix together ingredients, and there you have it! Serve with tortilla chips, or eat as a salad.