Cook macaroni in salted water per package directions until al dente. Drain well.
Meanwhile, in a small mixing bowl whisk together mayonnaise, buttermilk, pickle relish, salt, lemon pepper, granulated garlic, onion powder, sugar, dill and hot sauce.
To a large mixing bowl add macaroni, onion, red pepper, celery, peas and egg. Mix well.
Gently fold in dressing and tuna until evenly distributed.
Cover and chill for 4 hours or overnight.
Garnish with chopped green onion or dust with paprika and serve.