Legal Question in Administrative Law in California

Re: How do I file a motion ....

I believe your question relates to criminal law. The Penal Code contains a section (851.8) dealing with petitions for destruction of arrest records, making findings of factual innocence, etc., and I suggest you go to a law library and get an annotated version of the Penal Code and read the annotations of decisions interpreting Penal Code section 851.8. This will give you a better understanding as to whether the process fits your needs.

An ordinary citizen is probably authorized and entitled to file a petition under 851.8 in pro. per., but I think it would be desirable to engage a criminal defense lawyer. If you can't afford one, it's worth asking the public defender's office to handle it for you -- in some counties, they'll do that for low-income folks.