Meanwhile, heat remaining dressing in medium skillet. Add onions and garlic; cook and stir 5 min. or until onions are crisp-tender. Stir in broth; bring to boil. Add orzo; stir. Simmer covered on medium-low heat 7 min. Add asparagus; cook on medium heat 3 to 4 min. or until broth is absorbed and asparagus is crisp-tender. Add 1/2 cup cheese; cook and stir until melted.