Bring a pot of water to a boil, add the peeled and deveined shrimp, and poach for 2-3 minutes until pink and opaque.
Drain the shrimp and immediately plunge them into an ice bath to stop the cooking process.
Once cooled, pat the shrimp dry and chop into bite-sized pieces.
In a large glass bowl, whisk together the lime juice, lemon juice, olive oil, sea salt, and black pepper.
Add the diced cucumber, tomato, red onion, and minced jalapeño to the citrus mixture and toss gently.
Fold in the poached shrimp and chopped fresh cilantro, ensuring everything is well coated in the marinade.
Gently stir in the diced avocado right before serving to maintain its creamy texture and prevent browning.
Let the ceviche marinate in the refrigerator for 15-30 minutes to allow the flavors to meld beautifully before serving.