For a snack during a day at the beach, I recommend Kiosk #8, also called Silvia's. This place is towards the western end of the kiosks at Luquillo Beach, and is something of a walk, but it is worth it. I recommend the empanadas de carne (ground beef in pastry) and the Pio Nonos (meat wrapped in fried plantains). The homemade hot tamarind sauce goes with either dish. Kiosk #8 is run by a married couple; the husband has a good command of English, the wife less so.