Note: This all applies to the Kobo Wifi!
I would assume it's similar for the touch, but that is just an uneducated guess.
To answer your question directly: NO, you don't need to open it. That would probably be a bad idea even, some others tried (with success) and reported the device isn't really made to be opened up (i.e. something might break).
It is possible to activate the telnet daemon that is compiled into BusyBox, read below.
I suggest you read through the Kobo-related entries on this blog:
http://blog.ringerc.id.au
Especially this:
http://blog.ringerc.id.au/2011/01/en...s-to-kobo.html
and perhaps this:
http://blog.ringerc.id.au/2011/01/pr...nment-for.html
However, both are currently offline it seems. Google cache still has them, fortunately.
There is another one that explains how to copy the entire disc, though I've yet to try that myself.