Start by rinsing the cooked shrimp under cold water and patting them dry with paper towels. Remove any remaining shells or tails, and cut larger shrimp into bite-sized pieces while leaving smaller ones whole.

In a large mixing bowl, whisk together the mayonnaise, lemon juice, and Dijon mustard until smooth.

Stir in the garlic powder, paprika, salt, and pepper. Incorporate the finely diced celery and chopped chives, mixing gently.

Carefully add the shrimp to the bowl and gently fold them in with a large spoon or spatula. Be cautious not to overmix.

Taste and adjust seasoning as needed. Cover the bowl with plastic wrap and refrigerate for at least 30 minutes.