Rinse rice and barkey under cold water. In a saucepan, bring water to boil; stir in rice and barley. Cover and reduce heat; simmer for 40 minutes or until water is absorbed and rice is tender.
Spray 11 X 18 cm baking dish with nonstick vegetable coating; spread rice mixture on bottom.
In saucepan with a small amount of boiling water, cook zucchini, onions and green pepper for 2 to 3 minutes or until tender-crisp; drain. Spread over rice mixture.
In a small bowl, combine water, tomato paste, garlic, basil and sugar. Pour over vegetables. Arrange tomato slices on top. Cover and bake at 325oF for 25 minutes or until heated through. Sprinkle with cheese; bake uncovered for 5 additional minutes or until cheese melts.