In a saucepan, combine 3/4 cup sugar, 2 tablespoons cornstarch, and dash of salt. Stir in 1/3 cup water. Stir in 4 cups fresh or frozen unsweetened pitted tart red cherries, thawed. Cook and stir until thickened and bubbly. Cook and stir 1 or 2 minutes more. Cover; chill without stirring. Or use 1 (21 oz.) can cherry pie filling instead of sauce.