In a large saucepan, stir together punch, sugars, butter, water, vanilla, five-spice powder and cinnamon. Bring to a boil; reduce heat. Simmer, uncovered, until slightly syrupy and reduced to 2 cups, about 45 minutes.
Meanwhile, place a steamer basket in a Dutch oven. Add water to just below the basket. Bring water to a boil. Add yams to steamer basket; cover and reduce heat. Steam until yams are tender, 20 to 25 minutes.
Preheat oven to 350°. Arrange yams in a 2-quart baking dish. Sprinkle with salt. Pour candied yam sauce over yams. Bake, uncovered, until hot and bubbly, 30 to 40 minutes.