To uninstall task-finnish-kde-desktop just follow these instructions.
/debian/wheezy/main///install/index.html Finnish KDE desktop Debian 7.0 tasks 3.14.1
sudo apt-get remove task-finnish-kde-desktop
Which will remove just the task-finnish-kde-desktop package itself.
sudo apt-get remove --auto-remove task-finnish-kde-desktop
This will remove the task-finnish-kde-desktop package and any other dependant packages which are no longer needed.
If you also want to delete your local/config files for task-finnish-kde-desktop then this will work.
sudo apt-get purge task-finnish-kde-desktop
Or similarly, like this task-finnish-kde-desktop
sudo apt-get purge --auto-remove task-finnish-kde-desktop
|Maintainer||Debian Install System Team
|Description||Finnish KDE desktop|