Begin by bringing a large pot of salted water to a boil over high heat. Once boiling, add the rotini pasta and cook according to package instructions until al dente, usually about 7-9 minutes. Drain the pasta in a colander and immediately rinse it under cold water.

In a spacious mixing bowl, add the cooled rotini, making sure it's well-drained. Toss in the sliced pepperoni, diced mozzarella cheese, halved cherry tomatoes, black olives, diced green bell pepper, and finely chopped red onion. Mix everything together, ensuring each ingredient is well-distributed.

Pour the Italian dressing over the mixed ingredients. Toss the salad until all components are evenly coated. This will bring the vibrant colors and textures to life.

Sprinkle the dried oregano, along with salt and pepper to taste, over the salad mixture. Gently fold everything together again, ensuring the seasonings are well incorporated.

Cover the bowl with plastic wrap or a lid and place it in the refrigerator. Allow the salad to chill for at least 1 hour for the flavors to meld beautifully.

Before serving, remove the salad from the fridge and give it a final toss. Taste a small portion to check if any additional seasoning is needed.

Spoon the chilled Pizza Pasta Salad into serving bowls. This dish can be enjoyed as a light main course, a potluck favorite, or a fun side for barbecues.