In a large pot, bring salted water to a vigorous boil, then add medium shells pasta. Cook for 7-8 minutes until al dente, then drain and cool under cold running water.

In a large mixing bowl, combine the cooled pasta with imitation crab, thawed peas, chopped red onion, celery, and red bell pepper, folding gently to combine.

In a separate bowl, stir together mayonnaise and fresh dill, then fold the dressing into the pasta mixture until well-coated.

Taste and season with salt and pepper as needed, then cover and refrigerate for at least 1 hour to allow flavors to meld.

When ready to serve, stir the salad, garnish with chopped chives, and optionally add a drizzle of lemon juice.