LinuxTent

Ok, this is pretty easy
just install the rar library :

sudo apt-get install rar

rar package supports multiple volume archives and damage protection. It can also create SFX-archives. There are versions which run on DOS, Windows (3.1x,95,NT), FreeBSD, BSDI.

to make a  new rar archive

rar a new.rar file1 file2

to extract a rar archive file

rar  e new.rar

or you can make archives or extract them, by clicking right on the archives and choose from the menu, as you are doing with the .tar.gz archives