Pour the lime juice over the shrimp and cure in the refrigerator for 15-20 minutes, until the flesh turns from translucent pink to whitish (this is how it "cooks" in the acid).
Add the tomatoes, onion and chili and mix well.
Season with salt.
Just before serving, gently fold in the avocado so it does not turn to mush.
Sprinkle with fresh cilantro and serve with tortilla chips or in lettuce leaves.
A Receptnaptár original recipe. Calories and protein are estimated.