In large saucepan, combine 1 cup water and salt. Bring to a boil. Add sweet potatoes; return to a boil. Reduce heat; cover and simmer 8 to 11 minutes or until tender, stirring gently once during cooking.
Meanwhile, in small saucepan, combine cornstarch, brown sugar and ginger; stir until well mixed. Stir in 3/4 cup water and frozen juice concentrate. Cook over medium heat for 7 to 9 minutes or until sauce is thick and clear, stirring occasionally.
Drain potatoes; return to saucepan. Pour sauce over potatoes; mix gently to coat.