Watermelons are especially popular during the summer because of the fruit's cooling properties. The small, round watermelons sold here are firm and sweet - much better than the giant oval variety with seeds sold elsewhere. Watermelon juice is offered at many shops, and you can use this as a shortcut to make a lovely, refreshing granita (water ice). Make sure the vendor doesn't put too much sugar syrup in the juice or it won't freeze properly. Stir fresh lime juice to taste into the watermelon juice. Pour the mixture into a stainless steel metal tray with deep sides and place in the freezer. When the juice starts to freeze, stir with a metal whisk to break up the ice crystals. Do this every 20 minutes approximately, so the texture is light and icy but not solid. It should be ready in two to three hours. Scrape the mixture into an airtight plastic container and store in the freezer. At a memorable dinner cooked by the talented Justin Quek from Les Amis and Au Jardin in Singapore, the chef made a wonderful, simple dish of grilled watermelon. He served it on its own, but it makes a good counterbalance to rich meats. Cut thick rectangles of the fruit and grill over hot coals. The fruit won't burn because of its high water content. Sprinkle with crystal sea salt, preferably fleur de sel from Brittany, and serve warm.