Add diced celery, chopped red onion, and fresh dill to the bowl. Mix well.

Gently fold in the cooked shrimp until coated with the dressing.

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

Refrigerate the shrimp salad for at least 30 minutes to let the flavors meld.

Season with salt and pepper according to taste.

Serve the chilled shrimp salad over a bed of fresh lettuce leaves.