In a mason jar or mixing bowl, whisk or shake all dressing ingredients together until well blended. Taste and adjust—add sugar to mellow the tang, more vinegar for acidity, or olive oil for smoothness.
Cook rotini pasta in generously salted water according to package instructions until al dente. Drain well and transfer to a large bowl.
While the pasta is still warm, pour in HALF of the prepared dressing and toss to coat evenly. This helps the pasta soak up flavor.
Add pepperoni, salami, tomatoes, olives, bell peppers, red onion, pepperoncini, and mozzarella pearls to the bowl. Gently toss everything together until well combined.
Cover and refrigerate for at least 30 minutes or up to 24 hours. Keep the remaining dressing chilled separately.
Before serving, toss the salad with the rest of the dressing and top with freshly chopped parsley and grated Parmesan.