Bring a large pot of water to a boil. Cook tortellini until just tender, 8 to 12 minutes or according to package directions. Drain and rinse under cold water. Transfer to a large bowl.Advertisement
Meanwhile, place sun-dried tomatoes in a small bowl and cover with more boiling water. Let stand for 30 minutes. Drain and coarsely chop.
Add the sun-dried tomatoes to the tortellini along with artichoke hearts, roasted red peppers, tomatoes, scallions, basil and prosciutto, if using. Season with salt and pepper.
To prepare Tomato Vinaigrette: Working over a bowl, rub tomato halves on the large-holed side of a box grater until only the skins remain. Discard the skins. Add vinegar, oil, oregano, garlic, salt and pepper to the tomato juice and whisk until blended.
Add the Tomato Vinaigrette to the tortellini salad and toss. Serve the salad on a bed of arugula, if desired.
Make Ahead Tip: Cover and refrigerate Tomato Vinaigrette for up to 2 days.
1 1/2 starch, 2 1/2 vegetable, 1/2 medium-fat meat