Heat a large skillet over medium-high heat. Cook and stir beef and garlic in the hot skillet until browned and crumbly, 5 to 7 minutes; drain and discard grease. Add salsa and water; bring to a boil. Stir in macaroni; reduce heat and cover skillet. Simmer until macaroni is tender, 8 to 10 minutes. Stir cheese into mixture until melted.
