Rinse the cooked shrimp under cold water and pat completely dry with paper towels. Remove any remaining shells or tails. Cut larger shrimp into bite-sized pieces, leaving smaller shrimp whole. The key is achieving uniform pieces that will distribute evenly throughout the salad.

In a large mixing bowl, whisk together the mayonnaise, lemon juice, and Dijon mustard until smooth. This combination creates the signature tangy-creamy base that defines authentic deli-style shrimp salad. The mustard adds depth while the lemon brightens the overall flavor.

Stir in the garlic powder, paprika, salt, and pepper. Add the finely diced celery and chopped chives, mixing gently to combine. The celery should be diced small enough to provide crunch without overwhelming the delicate shrimp.

Add the prepared shrimp to the bowl and fold gently with a large spoon or spatula. Be careful not to overmix, as this can break apart the shrimp and create a mushy texture. The goal is to coat each piece evenly while maintaining the shrimp’s integrity.

Taste and adjust seasoning as needed. Cover the bowl with plastic wrap and refrigerate for at least 30 minutes. This chilling time allows the flavors to meld together and the salad to reach the proper consistency that makes it easy to spread or serve.