Would have no idea how to reach them? So does that mean that it is simply a shell company and that all the US tax and salary and other immigration issues are handled by CX in HK? or by the company in the US? confusing!!
If you're interetsed in working for CX based in the USA, don't bother. Recruiting is now done only at second officer level and all jobs offered are in HKG. You'd need years of seniority before you could even think of getting a based position in the USA - the same goes for Canada.
You can find telephone numbers for enquiries on the CX website or on Google.