Bring a large pot of salted water to a boil. Cook rotini until al dente.
Drain pasta and rinse under cool water. Shake off excess and let it dry slightly.
Whisk olive oil, red wine vinegar, Dijon, honey, Italian seasoning, salt, black pepper, and red pepper flakes.
Chop and prep mix-ins: tomatoes, cucumber, onion, olives, mozzarella, salami, pepperoncini, and parsley.
Combine cooled pasta with tomatoes, cucumber, onion, olives, mozzarella, salami, pepperoncini, and parsley in a large bowl.
Pour in the dressing and toss until everything is lightly coated. Taste and adjust salt and pepper.
Chill 20–30 minutes for best flavor. Sprinkle Parmesan before serving.