Bring a medium pot of salted water to a boil. Wash and dry produce. Cut mozzarella into ½-inch pieces. Once water is boiling, add tortelloni to pot. Reduce to a low simmer and cook until tender and floating to the top, 3-4 minutes. Drain and rinse with cold water. (TIP: Toss pasta with a drizzle of olive oil to keep from sticking together.) Carefully thread drained tortelloni, grape tomatoes, and mozzarella pieces onto skewers, alternating ingredients (you’ll have more pasta than tomatoes!). Place skewers on a serving platter. Season with pepper and drizzle with as much pesto as you like. Serve with any remaining pesto on the side for dipping.