I've never heard that you can do this with Samba. I've seen examples of it being done with BackOrifice, and other hacker tools, though. When you describe this, do you mean as a "crack" or compromise to a Windows system's security, or do you mean that you can configure Samba with the other user's cooperation to be able to "look" at their machine or take screenshots? I doubt that you can do either with Samba. It is just a Windows network share emulator for Unix.
In the original question, I'm not sure if
ohhdamn is specifically talking (1)about hacking Windows computers, or (2) the standard X-window method of accessing desktops over the network. If you mean the second choice, then yes, Linux and Unix machines can be set up quite easily to share their desktop environments over a network, with the X Windows system (or XFree86). This is quite a useful tool, because it allows users to "take their desktops with them" using any computer on the network. Often the desktop environments and the actual programs are on the server, while the end-user workstations are only thin clients, with only the necessary software to connect to the users' desktop profiles on the server. This makes it very easy to change offices, make demonstrations, etc...
If he is talking about the first possibility, hacking other computers and directly seeing their desktops, that is actually a kind of naive question. It's not a "can Linux do that" question, but an "Is that possible" question. It's not directly possible to just see someone's desktop data over a network, since computers don't by default send that data through the network, or all networks would be hopelessly clogged. However, if someone hacks into a Windows computer by command line, (or gets' that person to download a virus) he or she can install a piece of desktop-sharing software that can then allow a "stealth" connection to view the user's desktop. BackOrifice, as I said above, has been used to do this quite often. It has nothing to do with Linux, though.
These "destkop-sharing" tools are not necessarily evil cracker tools, but they can sometimes be used that way. Backorifice, used in a network, allows a single administrator to easily monitor many computers. VNC (Virtual Network Computing --
is another very interesting tool. It is a cross-platform desktop sharing tool that allows Windows users, Mac users, Unix users to share desktops or control one computer from another. It was developed by AT&T Laboratories in England. For example--you could enable VNC on your computer, then tell someone accross the world, to run the VNCViewer, connect to a certain IP address, and they can see your desktop and your mouse moving, or you could even allow that user to take temporary control of your computer.
Needless to say, all of these need to be used with extreme care, and they should be turned off or disabled when not specifically needed.