Cut remaining orange zest into thin (1 1/2x1/8-inch) strips to make about 1/4 cup. In 2-quart saucepan, place orange strips and 2 cups water. Heat to boiling. Drain and set orange strips aside. In same saucepan, heat sugar and vinegar over high heat to boiling. Reduce heat to medium; cook 5 minutes, stirring occasionally, until slightly thickened. Remove from heat; stir in orange strips and 1 cup orange juice.