Good luck with ticking off that box. It seems that most masseurs who identify as Asian are of Chinese or Thai background. Muscular Asian guys are a type for me - I don't know of any Asians on rentmasseur or rentmen, for that matter, who identify as Korean on the east or west coast of the US.
While I know that this isn't immediately helpful, put a trip to Seoul on your bucket list. I've had very nice experiences with Korean muscle guys from the massage sites that come and go there. Besides that, the food is good, the history is complex and interesting, the people are nice, and it is easy to get around by light rail in Seoul or to major cities by high speed rail.