Wait a minute... good ole Wikipedia, found it on there - Li hing mui is salty dried plum. It can be found in Hawaiian and Asian markets. It has a strong, distinctive flavor, and is often said to be an acquired taste, as it has a combination of sweet, sour, and salty taste. It has also been described as tart, and even tangy. Originally from China, the name "li hing mui" means "traveling plum". "Li hing" is "traveling" and "mui" is "plum." Li hing mui is also good for dry and scratchy throats, as it stimulates salivation.
Then then there was this little tidbit of info - There was also a cancer scare about li hing products; many people believed that li hing products could cause cancer. Yikes!