Bring a large pot of water to a boil and prepare an ice bath in a separate bowl.
Add the shrimp to the boiling water and cook for 2 minutes until pink and opaque, then immediately transfer to the ice bath to stop the cooking.
Once chilled, pat the shrimp dry with a paper towel and chop into 1/2-inch bite-sized pieces.
In a large glass mixing bowl, whisk together the lime juice, lemon juice, olive oil, sea salt, and black pepper.
Add the chopped shrimp to the citrus marinade and toss to coat thoroughly.
Stir in the diced cucumber, red onion, roma tomato, minced jalapeño, and chopped cilantro.
Cover and refrigerate for at least 15 minutes to allow the flavors to meld.
Gently fold in the diced avocado just before serving to ensure it remains intact and creamy.