Boil rotini in water with tablespoon salt until fully tender, about 10 to 12 minutes or package time. Drain thoroughly.
Whisk oil, vinegar, Dijon, oregano, dressing salt, and pepper. Toss warm pasta with half the dressing; spread in a shallow dish 10 minutes to stop steaming.
Transfer pasta to a large bowl. Fold in bell pepper, celery, tomatoes, red onion, provolone, and remaining dressing.
Toss again; serve at cool room temperature, or cover and refrigerate promptly at least 30 minutes for a colder salad.
Stir gently before serving; refrigerate leftovers within 2 hours.