If it's in a .var you have to open the var as an archive with 7zip or winrar or peazip, whatever archive program you have, and the textures will be in the same folder structure in there.
You can't access the textures for the built-in skins, as Vam only has a license to use the textures, not redistribute them. The only exceptions are the "Base male" and "base female" texture sets Meshed had made specifically for Vam users to mess around with. You'll find a folder for each in Custom\Atom\Person\Textures