
In a mixing bowl, combine mayonnaise, sour cream, lime zest and juice, dill, mustard, garlic, salt, and pepper to create the dressing. Set aside in the refrigerator.
Bring a pot of water to a boil. Add the shrimp and cook for 2 to 3 minutes until they turn pink.
Prepare an ice water bath while the shrimp are cooking. After cooking, transfer shrimp to the ice bath using a skimmer and let cool for about 3 minutes before draining.
Chop the cooled shrimp into bite-sized pieces and combine them in a mixing bowl with diced cucumber, green onions, and dressing until evenly coated.