Fill a large pot with water, add salt, and bring to a gentle simmer. Add the shrimp and cook for 2-3 minutes until pink and opaque. Transfer to an ice bath.

In a mixing bowl, combine mayonnaise, lemon juice, Dijon mustard, dill, salt, and pepper. Whisk until smooth and well blended.

Chop the cooled shrimp into bite-sized pieces. In a large bowl, fold the shrimp with the dressing, diced celery, and minced red onion.

Cover the mixture and chill in the refrigerator for at least 30 minutes.

Serve in lettuce cups, croissants, or over mixed greens.