In a large mixing bowl, combine the cooked shrimp, diced cucumber, cherry tomatoes, red onion, and fresh dill.
In a separate bowl, whisk together the mayonnaise, lemon juice, garlic powder, salt, and pepper until smooth.
Pour the dressing over the shrimp and vegetable mixture, and gently toss to combine until everything is well coated.
Cover the bowl with plastic wrap and refrigerate for at least 30 minutes to allow the flavors to meld.
Serve the salad on a bed of lettuce leaves if desired, and enjoy!