To remove the directory and files you will issue the following command. You will need to enter your root password
sudo rm -r {folder_name}
When you use the rm command to remove directories and files they do not get sent to the trash
Why do I need to use the terminal?
If your using a desktop environment you can just as easily right click on the directory and send the directory and it's contents to trash, however if a directory and it's files are owned by root then you would need to issue the rm command through the terminal as some Linux distributions do not allow to open a directory as root via the right click menu.
Another reason you would need to use the rm command is if you needed to delete a directory and it's files on a remote server.