I'm not really an expert in this area, because I don't know what special skills they need in class, but I would say knowledge of various disabilities would be one thing. A teacher that does not know what dyslexia is or does not know what an auditory processing disorder is, would not be good. I would think knowing the various types and understanding what skills/abilities are affected would be important.

The other thing I would recommend, is strong skills in terms of relating to parents. Good communication skills and interpersonal skills. Knowing how to approach parents would be important as well as being sensitive to the fact that this is an emotional thing for parents.

Good luck! I hope this helps.
Kathryn