Why would you believe that right to work states would not have teachers unions? It's true that a right to work state will probably not have unions the workers don't want, but that isn't the same thing.
Every state has public sector employee unions. The UAW is also in most right-to-work states. But the vast majority of employees (public and private) are not members of those unions and I'm positive that teacher contracts in RTW states are not collectively bargained.
http://www.myaea.org/
http://www.arizonaea.org/
http://www.aeaonline.org/
Why would you believe that right to work states would not have teachers unions? It's true that a right to work state will probably not have unions the workers don't want, but that isn't the same thing.
[1] I'm not cherry picking, just working down this list: http://en.wikipedia.org/wiki/Right-to-work_law#U.S._states_w...