Mix the cranberry sauce, sugar and 1/2 cup water in a saucepan over medium heat, until it's all blended together well and the sugar dissolves into the water. Save 2 or 3 whole cranberries for garnish, and put the rest of the contents in a food processor to puree it. Then, pour the mixture into an ice cream/sorbet maker-hopefully you have one, because it's the easiest way to make it. After about 20 minutes of the freezing/mixing process, you're good to go. Serve the sorbet in a glass and garnish it with the saved cranberries. Add fresh mint if you have it and want to be extra fancy.