Line a microwave-safe plate with a damp paper towel. Place the tortellini on the paper towel and top with a second damp paper towel. Microwave until the pasta is steamed and semi-soft, about 30 seconds. Thread one tortellini on a 6-inch skewer, followed by a mozzarella ball and grape tomato. Place on a serving platter and sprinkle with the basil chiffonade. Repeat with the remaining ingredients to make 9 more skewers. Drizzle with the balsamic reduction.