Coat a large Dutch oven with cooking spray; add oil, and place over medium-high heat until hot. Add onion and garlic; sauté 5 minutes or until tender. Add water and next 9 ingredients (water through lima beans); bring to a boil. Cover, reduce heat, and simmer 20 minutes. Add orzo; cook, uncovered, over medium heat an additional 10 minutes. Ladle soup into individual bowls, and sprinkle with cheese.
Note: Refrigerate remaining soup in an airtight container for up to one week, or freeze it for up to three months.