Place the shrimp in a bowl and cover with lime juice.
Allow shrimp to marinate for about 15-20 minutes until they turn opaque.
Dice the red onion, cucumber, and avocado.
Finely chop the jalapeños if using, and set aside.
Drain excess lime juice from the shrimp.
Add the diced onion, cucumber, avocado, and jalapeños to the shrimp.
Stir in the chopped cilantro and season with salt and pepper.
Mix gently to combine all ingredients.
Serve chilled with tortilla chips.