In 10-inch skillet, cook sausage over medium-high heat 5 to 7 minutes, stirring frequently, until no longer pink; drain.
Stir in uncooked pasta and sauce mix (from Hamburger Helper box), milk and hot water. Heat to boiling, stirring occasionally. Reduce heat; cover and simmer 15 minutes, stirring occasionally. Stir in green beans; cover and simmer about 10 minutes longer or until beans and pasta are tender. Stir in tomato. Remove from heat.
Cover; let stand 5 minutes (sauce will thicken as it stands).