The small, shiny black turtle bean is especially popular in Latin American cuisine, though it can also be found in Cajun and Creole cuisines of south Louisiana. It is often called simply the black bean (frijol negro, zaragoza, poroto negro, caraota o habichuela negra in Spanish, feijão preto in Portuguese), although this can cause confusion with other black beans.

The black turtle bean has a dense, meaty texture, which makes it popular in vegetarian dishes, such as the Mexican-American black bean burrito. It is a very popular bean in various regions of Brazil, and is used in the national dish, feijoada. It is also a main ingredient of Moros y Cristianos in Cuba, is a must-have in the typical gallo pinto of Costa Rica and Nicaragua, is a fundamental part of pabellón criollo in Venezuela, and is served in almost all of Latin America, as well as many Hispanic enclaves in the United States. The black turtle bean is also popular for making into soups. In Cuba, black bean soup is a traditional dish and it is served with white rice.

It is also common to keep the boiled water of these beans (which acquires a black coloring) and consume it as a soup with other ingredients for seasoning (known as sopa negra, black soup), as a broth (caldo de frijol, bean broth) or to season or color other dishes (aforementioned gallo pinto, for example).

Black turtle beans have recently been reported to be an extremely good source of nutritional antioxidants.[6]
Credit Wikipedia

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Black turtle beans, vastly different from the black beans used in Asian cuisines, have been a staple of Latin American cuisines for centuries.

The beans work perfectly in stews, sauces, salads and side dishes, but they also frequently appear in classic Latin dishes as a meat substitute. Wander around Brazil, and you’re bound to find the black turtle bean in the country’s national dish, feijoada (a stew of beans beef and pork). In Cuba, a Gallo Pintt (rice and beans fried with spices, chillies and onion). In Mexico, a black bean burrito.

http://www.essentialingredient.com.au/index.php/ingredients/black_turtle_beans/

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Soaking & Cooking
Black beans, like all dried beans, can be soaked before cooking. This  hydration helps to reduce the cooking time, but it does effect nutrient content and flavor adversely. Because they are small, 2-4 hours  soaking in cold water should suffice. Drain, and cook as per recipe. 

If you don't have the time, boil the beans in water for 1-3 minutes, turn off  heat, cover the pot and let them sit for one hour. Drain and proceed as per  recipe. However, there is a problem with this quick soaking (boiling for 1-3 minutes) method. Hot water increases the solubility of the water soluble  nutrients, and softens the cell membranes of the beans, further accelerating the  loss of these nutrients. This should be a consideration, because of the long cooking time during which more nutrients are lost. Cold soaked and cooked at a  very gentle simmer, beans retain most of their nutrients, which are  considerable.

To cook, drain the soaking water and add cold water, 1 part beans to 2 or 3  parts cold water. Bring to a boil, then reduce heat to a very slow simmer, so  the beans stay in their jackets. Simmer for 2 hours.
http://www.foodreference.com/html/artblackbeans.html