In 10-inch skillet, cook beef over medium heat 8 to 10 minutes, stirring occasionally, until brown; drain.
Stir in taco seasoning mix, water, salsa and corn. Heat to boiling; stir in rice. Boil 1 minute; remove from heat. Cover; let stand 8 minutes.
Fluff rice mixture with fork; sprinkle with cheese. Cover; let stand 1 to 2 minutes or until cheese is melted. Sprinkle lettuce around edge of skillet; sprinkle tomato in circle next to lettuce. Serve with sour cream.