It's depends. If you are searching outside Taipei, it is fairly easy to get a job before you arrive. I have recruiter contacts, they can get you a job easily, if you are interested PM me.
However, most schools in Taipei want an in person interview, except Hess. If you want to work in Taipei, its fairly easy to find a job, but I would recommend that you just come if you want a job in Taipei. and call Hess, Kojen, Stanford, Columbia and set up an interview. Where I am staying, Da'an, there are literally more than 100 cram school within a 5 mile radius (I am not exaggerating )