In a skillet over medium heat, cook the bacon until crispy, about 8-10 minutes. Transfer bacon to paper towels, then chop.

Bring a large pot of salted water to a boil; add tortellini and cook for 4-5 minutes until al dente. Drain and rinse under cold water.

In a large mixing bowl, combine mayonnaise, red wine vinegar, salt, oregano, Italian seasoning, garlic powder, and red pepper flakes. Whisk until smooth.

Add cooled tortellini, pepperoncini, Parmesan cheese, chopped onion, and tomatoes to the dressing. Fold gently until coated.

Cover and refrigerate the salad for at least 2 hours before serving. Stir and add additional dressing if desired.