In 10-inch skillet, cook beef over medium-high heat 5 to 7 minutes, stirring occasionally, until brown; drain. Stir in 2 tablespoons of the onions, 1 cup water, the garlic salt and gravy mix (dry). Cook, stirring constantly, until mixture thickens. Stir in potatoes, peas and tomato. Heat until hot; reduce heat to medium-low.