Cook the radiatore or corkscrew macaroni according to package directions; drain well. Return pasta to the warm pan. Gently stir in the cheese, tomatoes, green onions, oregano, and garlic.
Pour the milk into a jar that has a lid. Add the flour and salt. Cover and shake well to combine. Stir the milk mixture into the radiatore mixture. Cook, stirring gently, over medium heat for 3 to 4 minutes or until the cheese has melted and the mixture is thickened and bubbly. Makes 5 or 6 main-dish servings.