In a medium bowl, combine mayonnaise, lemon juice, lemon zest, dill, Dijon mustard, garlic, kosher salt, and black pepper. Mix until creamy and well-blended.

Bring a large pot of salted water to a rolling boil. Add the shrimp and cook for 2-3 minutes until pink and opaque. Drain and set aside.

Prepare an ice water bath. Plunge the cooked shrimp into the ice bath for 3 minutes to stop the cooking process.

In a large mixing bowl, combine the cooled shrimp, red onion, and celery. Pour the dressing over the mixture and toss gently.

Serve on butter lettuce leaves or in a bowl, garnishing with additional dill or lemon wedges if desired.