In a large skillet over medium heat, add the bacon strips and cook until crispy and golden brown, about 8–10 minutes. Transfer to a paper towel-lined plate to drain, then chop into pieces.

Bring a large pot of salted water to a boil. Add the frozen cheese tortellini and cook according to package directions, about 5–7 minutes. Drain and rinse under cold water.

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

Add the chilled tortellini, chopped bacon, sliced pepperoncini, diced tomatoes, red onion, and grated Parmesan to the bowl. Toss gently to combine.

Cover and refrigerate for at least 2 hours to allow flavors to meld.

Before serving, stir and taste; add reserved dressing if needed. Serve chilled, garnished with additional Parmesan and pepperoncini.