If using uncooked shrimp, bring a pot of water to a boil, add shrimp and cook for 2-3 minutes until pink and opaque. Transfer to an ice bath to cool, then chop into bite-sized pieces.

In a large mixing bowl, combine diced avocados, halved cherry tomatoes, chopped red onion, and diced cucumber. Add chopped cilantro or parsley and gently fold together.

In a small bowl, whisk together lime juice, olive oil, salt, pepper, and garlic powder if using, until well emulsified.

Add the chopped shrimp to the mixed vegetables and pour dressing over. Gently toss with a spatula to combine, taking care not to mash the avocados.

Serve immediately or chill for about 30 minutes to allow flavors to meld before serving.