Currently I'm running my own custom-made "desktop" with Xmonad, conky, and such like, and I don't use a file manager (not being a fan of the whole "manipulating icons to manipulate files" schema). Nevertheless, I remember back in my Gnome days that there was a convenient Gnome program that would allow me to view tarball (and other) archives on the Web from inside the file manager without downloading them. (Actually, it would download them to my temp directory, but I didn't have to think about that...) It was convenient because I could preview the contents of an archive (and even open files from it) without the bother of manually downloading it, unpacking it, and deleting all the files afterwards.

Is there perhaps some other minimalistic application out there that does something similar?

PeaZip is very minimalist. There is even a portable version.