I am an employer that has fired a foreign worker who has left the country and would like to ensure that his Work Permit is cancelled and revoke his Visa.
You can't, and why would you want to do that.
If it was a closed permit, then that person can no longer use it to work. If it was an open permit, it wasn't tied to you in the first place
You don't have the right to revoke a visa. As it mentioned above if he has a closed work permit he cant use it anymore however if he has a open work permit he can work anywhere as long as is valid.
I am an employer that has fired a foreign worker who has left the country and would like to ensure that his Work Permit is cancelled and revoke his Visa.