They are often used for braising, stir-frying, and grilling as kebabs.
The use, though, depends what part of the pig they are cut from. Some are tougher and are meant for stewing / braising. Some are more tender and are suitable for cooking on skewers (e.g. kebobs.)
For use in kebabs, the cubes should be about 3/4 inch (2 cm) big.
Braising ones will be bigger, about 1 inch (2 1/2 cm.) They should be simmered for about 40 minutes. You may wish to brown them before simmering them.