Bring a large pot of salted water to a boil. Add bowtie pasta and cook according to package directions until al dente (about 10-12 minutes). Drain and rinse under cold water to stop the cooking and cool the pasta. Drain well and transfer to a large mixing bowl.
In a small bowl, whisk together mayonnaise, red wine vinegar, olive oil, dried oregano, garlic powder, salt, and pepper until smooth and creamy.
To the bowl with pasta, add diced salami, cherry tomatoes, bell pepper, black olives, mozzarella, and red onion. Pour the dressing over the top and toss gently until everything is evenly coated.
Cover the bowl with plastic wrap and refrigerate for at least 30 minutes to allow flavors to meld. Just before serving, garnish with fresh basil and adjust seasoning if needed.