Boil a large pot of salted water, add tortellini, and cook according to package directions (3-5 minutes). Drain and rinse under cold water.

Soak the sliced red onion in cold water for about 10 minutes, then drain and pat dry.

Whisk together olive oil, red wine vinegar, Italian seasoning, salt, and pepper in a medium bowl until combined.

Combine the cooled tortellini, soaked red onion, deli meats, diced cheese, bell peppers, and cherry tomatoes in a large mixing bowl. Toss with dressing.

Cover and refrigerate for at least 1 hour to allow flavors to meld.

Before serving, give the salad a gentle toss, taste, and adjust seasoning if necessary. Serve chilled.