In small saucepan, combine sugar and cornstarch; mix well. Stir in water. Bring to a boil over medium-high heat, stirring constantly. Cook until thickened, stirring constantly. Stir in lime peel, lime juice and gingerroot.
In large bowl, combine oranges, bananas, strawberries and grapes; toss gently to mix. Pour lime mixture over fruit; toss gently. Serve immediately, or cover and refrigerate until serving time.