Several different beans are referred to as red beans, which can sometimes become a bit confusing. In the West, common beans with a naturally red shell such as kidney beans and Honduran red beans are known by this term collectively. In Asia, azuki beans are called by this name, and the red rice bean is also sometimes known as a “small red bean.” All of these beans have very similar nutritional properties, so it's hardly the end of the world if they get confused.
In the sense of common beans which are naturally red, red beans come from a New World vine which was domesticated in Central and Southern America. Beans formed a crucial part of the Native American diet for centuries, and a number of cultivars were developed in different regions; one of the most popular dishes made with these beans is red beans and rice, a favorite in the American South.
In Asia, the azuki bean is much more readily available than the New World red bean. Azuki beans are widely eaten throughout China and Japan, and they are prepared in a variety of ways, ranging from sweet red bean paste used to fill desserts to fermented bean paste for seasoning. In addition to the naturally red azuki bean, people also eat red rice beans, which are much smaller, but viewed as beneficial in Traditional Chinese Medicine.
Whatever variety of beans is under discussion, the beans are usually available in dried form. They need to be rinsed before cooking, to remove any detritus which might be leftover from the field, and they should ideally be soaked before cooking. Soaking cuts down on cooking time, and also helps the beans hold their shape, which can be useful in stews, where beans tend to fall apart if they are cooked too long. It is also advisable to cook beans until they are fully tender, because undercooked beans tend to create undesirable gastrointestinal effects.
You can grow red beans at home very easily. Beans thrive in many climates, with most garden supply stores carrying a variety of bean cultivars to choose from. To grow beans, you will need a sunny spot with well-drained soil and some support, such as stakes, a trellis, or even a network of taut strings. The beans should be started in the spring, after the last chance of frost is over. They may be eaten immature, at the green stage, or allowed to fully mature and dry on the vines; the dried bean pods can be picked and cracked open to extract the beans for storage.