Cook pasta to desired doneness as directed on package. Drain.
Meanwhile, heat oil in large skillet over medium-high heat until hot. Add onion; cook and stir 2 minutes. Add potatoes; cover and cook 5 to 6 minutes or until partially cooked, stirring occasionally.
Stir in asparagus, bell pepper, oregano, salt and pepper. Reduce heat to medium-low; cover and cook 5 to 8 minutes or until vegetables are tender, stirring occasionally.
Stir in cooked pasta; cook until thoroughly heated. Remove from heat. Sprinkle with cheese. Cover; let stand until cheese is melted.