How To Poach The Shrimp: Fill a large stockpot halfway with water and bring it to a boil. Add the shrimp boil and kosher salt. Reduce the heat to a gentle simmer and add the shrimp. Poach for 4-5 minutes until the shrimp are opaque and curl into a "C" shape.
Remove the shrimp and spread them on a baking sheet to chill while preparing the other ingredients.
Mexican Shrimp Cocktail Tomato Sauce: In a large bowl, whisk together the orange soda, tomato juice, ketchup, and fresh lime juice to form the base of the shrimp cocktail juice. Taste and adjust the seasoning as needed.
Add the finely diced white onion, small diced roma tomatoes, diced jalapeno (seeded if preferred less spicy), and avocado to the juice. Chop fresh cilantro and add about 1/4 cup or adjust to your taste. If you don't like cilantro, you can skip it as there is no substitute for its unique flavor.
Once the shrimp are chilled, peel and devein them if necessary. You may chop the shrimp into smaller pieces if desired. Add the shrimp to the tomato sauce and fold in the fresh veggies. Taste again and adjust seasoning with more salt or lime juice if needed. You can marinate it in the refrigerator overnight or serve immediately.
Serve this dish chilled with tortilla chips. It can be enjoyed with a spoon or scooped up with tortilla chips. In the Yucatan, it's traditionally served with very crisp, thick corn tortilla chips available at Mexican grocery stores. For a beautiful presentation, serve in tall glasses to showcase the vibrant colors. Enjoy!