userdel

This command allows you to delete a user's account.

Options

-r recursive removal of home directory

If you wanted to remove joe and all of the files in the home directory you would use this command.

userdel -r joe

Note that the removal of a user and their home directory does not remove files and directories owned by that user on the system, so keep that in mind as those remaining files and directories will need to have the ownership changed.