Begin by cooking the rotini pasta in a large pot of boiling salted water, following package instructions until al dente, approximately 8-10 minutes. Once done, drain the pasta and rinse it under cold water to halt the cooking process.

In a large mixing bowl, combine the cooled rotini, sliced pepperoni, diced mozzarella cheese, halved cherry tomatoes, sliced black olives, chopped green bell pepper, and diced red onion. Stir gently to mix the ingredients thoroughly.

Pour the Italian dressing generously over the mixed ingredients in the bowl. Toss everything together carefully, ensuring that every piece is coated in the zesty dressing.

Sprinkle in the dried oregano, and season with salt and pepper according to your taste. Mix gently again to distribute the seasonings evenly throughout the salad.

Cover the bowl with plastic wrap and refrigerate the Pizza Pasta Salad for at least one hour to allow the flavors to meld beautifully.

Before serving, give the salad another gentle toss to refresh the mix. Check and adjust the seasoning if necessary, and serve cold.