Bring a large pot of water to a boil, add the kosher salt, then add the elbow macaroni and cook according to package directions until al dente.

Drain the macaroni in a colander, rinse under cold water until completely cool, and let it drain very well.

In a small bowl, whisk together the mayonnaise, Dijon mustard, 1 1/2 tablespoons Cajun seasoning, lemon juice, hot sauce, sugar, garlic powder, onion powder, and black pepper until smooth.

In a large mixing bowl, combine the cooled macaroni, celery, red bell pepper, green bell pepper, red onion, dill pickles, hard-boiled eggs, cheddar cheese, parsley, and green onions.

Pour the dressing over the macaroni mixture and gently fold with a rubber spatula until everything is evenly coated.

Taste and add the remaining 1/2 tablespoon Cajun seasoning or additional salt and pepper if needed, adjusting spice level to your preference.

Cover the bowl tightly and refrigerate the macaroni salad for at least 1 hour to chill and allow the flavors to meld.

Before serving, give the salad a gentle stir and, if it seems dry, add a spoonful or two of mayonnaise or a splash of milk to loosen the texture.