No, Skymark does not hire expat FO's. Right now, they have 2 sources of copilots: 300 hour Japanese pilot's who just received/converted their Multi-Engine/Instrument/Commercial into a JCAB license; or the 40 or so ex-JAL copilot's that were fired from JAL because they were un-upgradeable. They will soon be starting an Ab-Initio Cadet program as well. It's a #$% job enough as it is as a Captain, I can't even imagine how horrible it would be to be an FO there.
On a side note, you don't really want to be an FO in Japan unless you are working with an established company like AJX or NCA where they have an expat upgrade program. FO's in Japan usually consists of PM duty about 99% of the time, having to do a lot ground-duty (FO's at Skymark have to do one year of ground duty prior to starting training and do about 4 months of Flight Attendant/Check-In duty prior to upgrading as a Captain - the CEO's way of saying "FU, you are my bitch" to the pilot group), not to mention endless unpaid Sim support for Captain training, de-briefings by the Captain after every flight on what you did wrong and what he didn't like, etc.