Can I tell my boss, "with all do respect, fire me then".
Wow that is brave. What is your reason for asking to be fired?
I want to leave, but I do it in a polite way.
Its not great to talk back to your boss, however if you do want out of your job this is one way. Another polite way would be to simply be honest with them and let them know that you would like to leave.
Then what do you think of writing a letter.
That will be a better way to leave a job. If you talk back to the boss he might give you a bad recommendation for your next job.