Do not come to Cuba for fine dining. While it's possible to minimize the pain, finding good food, service, and value is a challenge in Cuba. Most restaurants that cater to tourists are run by large state-owned corporations, and as a whole they are often overpriced and mediocre. Even the popular and highly touted restaurants here often suffer from inconsistency and indifferent service. Note: Be especially on the lookout for overcharging, either in the form of phantom charges or inflated prices.
In addition to hotel restaurants and official state-run tourist restaurants, the principal dining option in Cuba is the paladar. Like casas particulares, paladares are private homes that have been granted permission to serve foreign tourists. Paladares are small, with a seating limit of just 12, and subject to various limitations. They cannot serve shrimp or lobster for instance, and cannot accept credit cards. They are also heavily taxed by the state. However, Cubans are a creative lot and you will find paladares that have figured ways around many of these limitations. Paladares tend to open and close, move, or change their name or menu with great frequency. They also often run out of menu items, or simply can't find the raw materials to begin the day with. However, there are some dependable and long-standing paladares. In fact, several of these are among the best restaurants in the country. At these, you'll almost certainly need a reservation, or be prepared to wait.
In general, you should tip between 10% and 15%, keeping in mind that this represents a huge amount of hard currency for most Cubans. Some restaurants add a 10% service charge to bills; whether or not it's actually given to the waitstaff is questionable. Also, if you show up at a paladar on the recommendation of a taxi driver or jinetero, they will expect a commission of between CUC$3 and CUC$5, which is often added to your bill.
Given the unique economic and social conditions of Cuba, there is little street food to speak of, aside from a few odd pizza and ice-cream vendors. Cuban street pizza features heavy dough, with a molten mess of sauce and gooey cheese topping, served as small individual discs on wax paper.
With a recent influx of foreign capital and a move toward modernization, fast-food chains have begun popping up around Cuba. The most prominent of these is El Rápido, which has numerous outlets serving fried chicken, burgers, hot dogs, microwave pizzas, and other fast-food staples. Another chain worth mentioning is Pizza Nova, which has several outlets in Havana and in various provincial cities. This chain specializes in thin-crust pizza and good pastas.