It might vary from each department, but if you can perform the duties of a police officer I don't see why not. I would imagine they would have you undergo a lot of medical examinations covering the area that caused your discharge.
You are going to have hard time getting a job. As an asst. manager you should know all the rules. Also remember that its hard right now for people to get a job, there are plenty of people that a spotless record that probably will be hired first.
I don't want to say you don't have a chance, it could take a little longer than you expect. What you need to remember is that there are plenty of applicants that have a spotless record that will get hired before you.