Cut up shrimp in 2-3 pieces, wash, and put in a big pot or bowl.
Squeeze the lemons into a bowl and squeeze until the lemon juice covers the shrimp lightly. Cover the bowl with the shrimp and lemon juice and put it to the side for about 1hr (or until the shrimp looks pink/orange)
While the shrimp cooks, chop the cilantro very thin. Chop the cucumber, tomato and union into small squares.
Cut avocado into small squares and set aside.
After the shrimp is pink. Add all of your other ingredients: Cilantro, cebolla, tomato, cucumber and union, and your bottle of Clamato.
Mix and add salt and pepper to your taste. Serves 3-4 people or more depending on how much they eat. You generally eat it with tortilla chips and enjoy.