1. Using kitchen shears or a sharp knife, cut along the back of the shrimp shells to expose and remove the veins.
2. Prepare an ice bath large enough to hold all shrimp.
3. In a medium pot, bring 2 quarts water, lemon wedges (juice squeezed in and wedges added), black peppercorns, kosher salt, and reserved cilantro stems to a rolling boil.
4. Add shrimp to the boiling water, cover, and remove the pot from heat. Let shrimp poach gently for 3 minutes or until shrimp turn pink and opaque.
5. Immediately transfer shrimp to the ice bath and chill for 3 minutes to stop cooking. Peel shrimp, including tails, if preferred.
6. In a medium bowl, mix together diced tomatoes, cucumber, red onion, vegetable juice, Worcestershire sauce, ketchup, lemon juice, lime juice, water, and hot sauce. Add peeled shrimp and stir gently to combine.
7. Cover and refrigerate the mixture for 30 minutes to up to 24 hours to allow flavors to meld.
8. Before serving, remove from refrigerator and let stand 10 minutes at room temperature. Stir in diced avocado and chopped cilantro leaves. Adjust seasoning with salt and black pepper as desired.
9. Serve chilled in cocktail glasses or bowls with tortilla chips and lime wedges on the side.