expunged misdemeanor - work permit/greencard Criminal Records, Expungement

Dear NYClex,

Thank you for all the other questions that you have answered, but may I ask one more.
I have a dismissed misdemeanor charge and im not a us citizen. I was wondering whether I should tell this to my future employer. They will be sponsoring me for the greencard and I should start working for them soon. However, I don't really know how the whole work permit process works.
If they apply on my behalf, will the be told that I need to be fingerprinted or something?
I know that my record is clear, and they as employers - shoud they decided to do the background check - won't see anything. However, is it different for work permit process, do they get access to all information?
Also, does having an expunged record pose a problem for getting the work permit?

Thank you

 

Thank you for your help.
I guess I was just wondering whether there's a way to do it without informing the prospective employer of all bad details.
but i guess its my fault this happened in the first place.
Thanks again