Best Cuban food in Sin City... any better and you'll hafta travel to 'La Saguecera' (the predominantly Cuban section of Miami-Dade County, Florida - a Cubanized 'corruption' of 'southwest').
You can never go wrong with their Sandwich Cubano, moros y cristianos (black beans and rice) and other popular Cuban meals. Service is excellent (even more so if you speak Spanish!) though the 'Naked City' location north of the Strip can be very sketchy, especially at night.