Bring a pot of water to a boil, poach the shrimp for 2 minutes until pink and opaque, then immediately transfer to an ice bath to stop the cooking process.
Once chilled, peel and devein the shrimp if necessary, then dice into bite-sized pieces and place in a large glass mixing bowl.
Squeeze the juice from the limes and lemon over the shrimp, ensuring the pieces are well-coated, and let marinate in the refrigerator for 15 minutes.
Finely dice the red onion, cucumber, Roma tomato, and jalapeño, removing the seeds from the jalapeño if you prefer less heat.
Remove the shrimp from the refrigerator and fold in the diced vegetables, chopped fresh cilantro, and extra virgin olive oil.
Gently dice the avocado and fold it into the mixture last to prevent it from mashing, keeping the cubes intact.
Season with sea salt and black pepper, tossing lightly to combine all the flavors.
Serve immediately in chilled bowls for the best texture and temperature.