In a large skillet heat oil over medium-high heat. Add onion; cook and stir 3 minutes. Add garlic; cook and stir 1 minute. Add lamb; cook 3 to 5 minutes or until brown on all sides. Stir in the next six ingredients (through black pepper). Bring to boiling; reduce heat. Simmer, covered, 10 minutes, stirring occasionally.
Stir in asparagus and sweet pepper. Cover and simmer 3 to 5 minutes more or until vegetables are crisp-tender. Fluff lamb mixture lightly with a fork. Top with fresh oregano, if desired, and serve with lemon wedges.