i have a remote linux apache server. and i have some .zip and .tar
files on the server. i have full ftp access. is there a way i can
deflate/unpack those archives on the server instead of downloading them
to my pc then unpacking then uploading back again?

If you are on a linux box, then you should have ssh/shell access. If
so, run

unzip MYFILE.zip
tar xvf MYFILE.tar
tar zxvf MYFILE.tar.gz

If you have a control panel (assuming that you do have one), look in
there to see if you can extract the compressed file through that
interface.

its a remote linux apache server and it only has mysql databases, and
php scripting. there is no ssh/shell acess.
and i only have ftp.