Eliminate or hide fields or modules in Job Openings Module

Eliminate or hide fields or modules in Job Openings Module

I'm trying to eliminate or hide some fields like "Account Manager" or "Forecast Detail" set of fields because we don't need them but I can't.
I know that some fields are de "System Defined" but even in this case we don't need them for our daily activity.
Is there any way to eliminate or hide them?
Thank you
Norberto