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

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

While the pasta cooks and cools, prepare the vegetables by halving the cherry tomatoes, dicing the bell pepper and red onion, slicing the celery, olives, and green onions, and chopping the parsley.

If using chicken and andouille sausage, cook or reheat them as needed, then dice or slice into bite-size pieces and let cool slightly.

In a small bowl, whisk together the mayonnaise, sour cream, Dijon mustard, lemon juice, olive oil, Cajun seasoning, smoked paprika, garlic powder, onion powder, cayenne, salt, and black pepper until smooth and well combined.

Place the cooled pasta in a large mixing bowl and add the cherry tomatoes, bell pepper, red onion, celery, black olives, green onions, parsley, chicken, and sausage.

Pour the dressing over the pasta mixture and gently toss with a wooden spoon or spatula until everything is evenly coated.

Taste the salad and adjust seasoning with additional salt, black pepper, or Cajun seasoning as desired.

Cover the bowl tightly with plastic wrap or transfer the salad to an airtight container and refrigerate for at least 30 minutes to allow the flavors to meld.

Before serving, give the salad a final stir, add a splash of lemon juice or a spoonful of mayonnaise if it looks dry, and garnish with extra green onions or parsley if desired.