Cut a seedless watermelon in half, and scoop out melon using a melon-baller.Assemble the skewers in this order: watermelon ball, fresh basil leaf, mozzarella ball, folded slice of prosciutto, and so on. (Every skewer will have just 1 slice of prosciutto)Drizzle skewers with olive oil and balsamic marinade.Serve immediately or cover and refrigerate until ready to serve.