This simple recipe was inspired by the traditional kalua pork of Hawaii, for which a whole pig is rubbed thoroughly with salt and baked in an underground pit. In this dish, the salt combines with the slow cooking to make the pork incredibly tender and flavorful. Don't use a leaner cut of pork, such as pork loin or tenderloin, or the meat will be dry. These tacos are also terrific with a mango or other fruit salsa.