Bring a large pot of salted water to a rolling boil.

Add the shrimp and boil until they turn pink and opaque — about 1.5 minutes for fresh shrimp and 3 minutes for frozen shrimp.

Drain the cooked shrimp and cool them under cold running water for 1 minute. Pat dry with a paper towel and refrigerate until ready to mix.

In a large bowl, combine finely chopped celery, mayonnaise, Greek yogurt, chives, dill, lemon juice, Dijon mustard, and season with salt to taste.

Gently fold in the cooled shrimp and sliced cucumber. Season with additional salt and pepper to taste.