If you do not wish to continue with GNOME environment then it's best to work with command line interface to face the real-life challenges. Before you proceed, make sure that you logged in as a root user or you have use sudo command with the root password. Open terminal to un-install GNOME and type, apt-get remove gnome-shell and then type apt-get autoremove This will remove GUI interface from Kali Linux and you are set to work through command line interface.