Bring water to a boil in a small pot. Add the shrimp, cover and turn the heat off. Leave the shrimp in the water for 5 minutes and drain.
In a medium bowl, place the shrimp, onion, salsa rosada, cilantro, parsley, salt and pepper. Mix well.
Cut the avocados lengthwise and remove the pit, drizzle with the lime juice and sprinkle with salt and pepper.
Place the lettuce in a serving plate and place the avocados on top. Fill each avocado with the shrimp mixture.
Sprinkle with fresh cilantro and serve immediately.