You are / were fired

[Hansman]

You are fired. Get out of this office.

Is the expression You are fired right in meaning and grammar, especially tense?

Shouldn't it be 'You were fired'?

Is 'You are fired' used as an fixed expression or a strange sort of passive voice?

 

[Tarheel]

In direct speech, "You're fired!" is the common, most likely expression. (The other one is not used.)

 

[teechar]

You are fired.

The act of dismissal is happening now.

You were fired.

The act of dismissal happened before.

Is 'You are fired' used as an a fixed expression

Yes, it is pretty standard for that kind of context.

or a strange sort of passive voice?

You can analyze it that way if you like, or you can view "fired" as an adjective. It makes no difference to the meaning.