You can uninstall or removes an installed cronic package itself from Ubuntu 16.10 (Yakkety Yak) through the terminal,
$ sudo apt-get remove cronic
If you would like to remove cronic and it's dependent packages which are no longer needed from Ubuntu,
$ sudo apt-get remove --auto-remove cronic
If you use with purge options to cronic package all the configuration and dependent packages will be removed.
$ sudo apt-get purge cronic
If you use purge options along with auto remove, will be removed everything regarding the package, It's really useful when you want to reinstall again.
$ sudo apt-get purge --auto-remove cronic