Preparation In a saucepan bring sugar and water to a boil, stirring until sugar is dissolved, and cool syrup. Chop coarse enough of cucumbers to measure 6 cups and in a blender purée with syrup in 2 batches until smooth. Transfer purée to a shallow metal baking pan and stir in liqueur. Freeze mixture, covered, stirring and crushing lumps with a fork about every 30 minutes, until mixture is firm but not frozen hard, 2 to 3 hours. Granita may be made 2 days ahead and kept frozen, covered. Just before serving, scrape granita with a fork to lighten texture.
Preparation In a saucepan bring sugar and water to a boil, stirring until sugar is dissolved, and cool syrup. Chop coarse enough of cucumbers to measure 6 cups and in a blender purée with syrup in 2 batches until smooth. Transfer purée to a shallow metal baking pan and stir in liqueur. Freeze mixture, covered, stirring and crushing lumps with a fork about every 30 minutes, until mixture is firm but not frozen hard, 2 to 3 hours. Granita may be made 2 days ahead and kept frozen, covered. Just before serving, scrape granita with a fork to lighten texture.