Bring a large pot of salted water to a boil. Cook tortellini according to package directions until just tender, usually 3-4 minutes for fresh or 7-9 for frozen. Drain immediately and rinse under cold water to stop cooking. Shake colander well to remove excess water, then spread tortellini on a clean kitchen towel to cool completely - about 10 minutes.

In a large mixing bowl, whisk together olive oil, red wine vinegar, reserved pepperoncini brine, oregano, garlic, salt, and black pepper until emulsified - about 30 seconds of vigorous whisking. The brine adds that signature grinder tang, so don't skip it.

Add cooled tortellini to the bowl with dressing and toss to coat. Let sit 5 minutes so the warm pasta absorbs some flavor. Add salami, provolone, cherry tomatoes, pepperoncini, and red onion. Fold everything together gently but thoroughly.

Let salad rest at room temperature for 15 minutes, or refrigerate up to 4 hours if making ahead. To serve, spoon over chopped romaine on individual plates or fold the lettuce in just before serving for a picnic-style presentation.