In a skillet, cook diced bacon over medium heat for 8–10 minutes, or until crispy and golden brown. Use a slotted spoon to transfer bacon to a paper towel-lined plate to drain excess grease.

Bring a large pot of salted water to a rolling boil. Add cheese tortellini and cook according to package instructions, approximately 3–5 minutes. Drain and rinse under cold water to stop cooking.

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

Add cooked tortellini, cooled bacon, pepperoncini, grated Parmesan cheese, red onion, and sliced tomatoes to the dressing. Gently fold to combine.

Cover salad with plastic wrap and refrigerate for at least 1 hour to enhance flavors.

Before serving, stir the salad gently and serve cold or at room temperature.