In a large mixing bowl, combine shredded imitation crab meat, mayonnaise, and Dijon mustard. Stir until thoroughly coated.

Finely chop the celery and red bell pepper, then add them to the crab mixture. Squeeze in fresh lemon juice and sprinkle garlic powder, salt, and pepper. Fold gently.

If using fresh dill, chop it and fold it into the salad.

Cover with plastic wrap and refrigerate for at least 30 minutes to allow the flavors to meld.

Serve on a platter of crisp lettuce leaves or use as a filling for sandwiches.