Brown ground beef in large nonstick skillet; drain. Stir in salsa and corn. Remove beef mixture from skillet; set aside.
Add water, milk and margarine to same skillet and bring to a boil over high heat. Stir in Knorr® Pasta Sides™ - Cheesy Cheddar. Return to a boil. Reduce heat to medium and cook, stirring occasionally, 10 minutes or until pasta is tender.
Stir in beef mixture; heat through. Stir in cilantro and serve, if desired, with sour cream.