Bring a large pot of salted water to a boil. Cook the tortellini according to package instructions until just tender. Do not overcook. Drain immediately and rinse briefly with cool water to stop the cooking. Let drain completely in a colander.

While the pasta cooks, prepare the vegetables: halve the cherry tomatoes, dice the cucumber, thinly slice the red onion, and if using, cut the salami or pepperoni into small strips.

In a large mixing bowl, combine the cooled tortellini, tomatoes, cucumber, onion, olives, mozzarella (if using), and salami or pepperoni (if using). Toss gently to distribute.

Pour about half of the Italian dressing over the salad and toss gently to coat. Let sit for a few minutes, then add more dressing as needed. Be careful not to overdress; the tortellini will absorb some dressing over time.

Cover the bowl and refrigerate for at least 30 minutes to allow flavors to meld. Before serving, toss again and adjust seasoning with salt and pepper if needed.

Just before serving, sprinkle fresh parsley or basil over the top. Do not mix in the herbs too early to keep them bright.