Cook Pasta: Bring a large pot of salted water to a boil. Add rotini pasta and cook according to package instructions, about 8-10 minutes until al dente. Drain and rinse under cold water.

Bake Bacon: Preheat oven to 400°F (200°C). Lay bacon on a lined baking sheet and bake for 12-15 minutes until crispy. Let cool, then chop into pieces.

Prep Vegetables: Slice green onions, dice cucumber, chop celery, and finely chop parsley. Set aside in a large bowl.

Make Dressing: In a separate bowl, combine mayonnaise, mustard, apple cider vinegar, salt, pepper, and smoked paprika. Whisk until smooth.

Combine Ingredients: In the bowl with vegetables, add cooled pasta and bacon. Fold in dressing until well-coated.

Adjust and Serve: Taste and adjust seasoning as necessary. Serve immediately or chill for 30 minutes before serving.