Peel and cut cooked sweet potatoes into large pieces. Place apricots, orange juice, water and honey in a saucepan. Bring to a boil. Reduce heat, cover, and simmer until apricots are soft, about 25-30 minutes. Remove from heat. Arrange sweet potatoes in a baking dish. Sprinkle with walnuts, if desired. Pour apricot sauce over the top. Cover. Bake at 350 degrees until heated, about 15-20 minutes.