Prep the Shrimp: Rinse the thawed shrimp under cold running water and thoroughly squeeze or pat dry with paper towels to remove excess moisture so your cocktail isn't watered down. Do this with raw or cooked shrimp.
Marinate Shrimp: Dice shrimp if large and place it into a large glass (non-reactive) bowl. Use a citrus squeezer to get 1 to 1 ¼ cups lime juice from 6 limes over shrimp. Stir to combine then cover and marinate in the refrigerator (marinate 1 ½ to 2 hours for raw shrimp or until no longer translucent and marinate 15 minutes for cooked shrimp), stirring halfway through.
Chop the vegetables: cucumber, avocado, tomatoes, red onion, jalapeno, and cilantro. A food chopper will make this process much faster.
Combine: When shrimp are done marinating, add vegetables to the bowl along with clamato juice and stir to combine. Serve with hot sauce if desired along with tortilla chips or over tostadas.
