Puree the cantaloupe in a blender until smooth. In a mixing bowl, combine the wine and sugar and stir until the sugar has dissolved; allow the bubbles time to settle. Add the pureed cantaloupe, the lime juice and the lime zest to the bowl. Stir well.
Pour the mixture into a 9-by-13-by-2-inch baking dish. Freeze for 2 hours. Remove from the freezer and, using a fork, scrape the granita into flakes. Freeze for another 2 to 3 hours.
Serve the granita in martini glasses, garnished with a mint leaf.