1. Cook and drain macaroni according to manufacturer's directions.
2. Sprinkle macaroni with half the dill weed and chill in the fridge.
3. Mix together Miracle Whip, celery salt, and remaining dill. Add tuna and onion to dressing mixture.
4. When macaroni is cooled, stir in dressing mixture. Add green pepper, cucumber, and cheddar.
5. Cover and chill.