Combine orange juice, 3/4 cup water, honey, sugar, and orange peel in blender. Add half of strawberries and half of raspberries; puree until almost smooth. Add remaining berries; puree until smooth. Pour mixture out onto 13x9x2-inch baking pan. Freeze until edges are icy and center is slushy, about 1 hour 30 minutes. Stir icy edges into slushy center. Freeze granita until solid, stirring every 45 minutes, about 3 1/2 hours longer.
Using fork, scrape granita down length of pan, forming icy flakes. Cover and freeze at least 1 hour and up to 2 days. Spoon granita into glasses.
