COMBINE orange juice, sweetened condensed milk, lemon juice, orange peel and rose water, if desired, in large bowl; mix well.
POUR into 9-inch square baking pan. Cover and freeze just until edges are frozen, about 1 1/2 hours. Using a fork, scrape frozen granita toward center to break up ice crystals. Pat mixture evenly into pan. Cover and freeze. Repeat every 30 minutes until granita is firm, about 4 hours.