Is there a word that should be used on this board in place of analingus (eating ass)?

Are you serious? How do you know you're not referring to Asians themselves.

Completely, just as "French", "Greek", and "Russian" don't refer to people from France, Greece, or Russia (in this context).  Here's a link for you to brush up on acronyms and jargon.

So if I ask "do you speak Asian", am I asking if she will do it to me or if I can do it to her?

Technicalities!! I'd say that, in general, the one who does the "speaking" or "gives a lesson" is the one doing it to the other.  Greek and Russian, on the other hand, aren't ambiguous in this sense.

Do providers usually know these terms also? For example if I asked her over the phone would she know what I'm talking about?

I'd be very surprised to find a provider who didn't.  However, you'd be well advised to be careful about what you ask and how you ask it, especially when conversing with a provider who doesn't know you - sexually explicit questions and comments are generally taboo.  Many providers advertise the "languages" they speak on their websites and in their postings here, although your particular dialect isn't commonly seen.  Above all, comport yourself as a gentleman and be respectful, not crude.  Wait until you've established a rapport before getting specific about anything that isn't mentioned publicly.