Bring a pot of water to a boil and poach the shrimp for 2 to 3 minutes until pink and opaque.
Immediately transfer the shrimp to an ice bath to stop the cooking process, then chop into bite-sized pieces.
In a large glass bowl, whisk together the lime juice, extra virgin olive oil, sea salt, and black pepper.
Add the chopped shrimp, red onion, cucumber, and tomato to the bowl, tossing well to coat in the lime marinade.
Let the mixture marinate in the refrigerator for at least 15 minutes to allow the flavors to meld.
While the ceviche marinates, slice the corn tortilla into triangles and bake at 375 degrees Fahrenheit for 8 to 10 minutes until crisp.
Just before serving, gently fold in the diced avocado and fresh cilantro to maintain their texture.
Serve the chilled ceviche in a bowl alongside the warm, crunchy tortilla chips.