Screen sharing with windows 8.1 - observe windows screen on mac

Here are already some questions about how to connect to mac's screen from windows, like:

• screen sharing from Windows to Mac over LAN


• Screen Sharing from windows to mac with no software on the windows computer

I'm looking for a reverse way. My wife got a new windows 8.1 notebook, and i'm looking for a way how to

• connect to her notebook from my Mac


• observe what she doing and allow remote assistence from my MAC


• in short - the same functionality as the /System/Library/CoreServices/Applications/Screen\ Sharing.app does with another mac. (e.g. vnc://... )

What i need to install and/or configure in the windows notebook to got the ability share the windows 8.1 screen, e.g. what allows me doing the following:

$ smbutil lookup wifebook
Got response from 192.168.1.13
IP address of wifebook: 192.168.1.13
$ open vnc://192.168.1.13

Any ideas?

(ps: while i'm pretty familiar with UNIX like systems, i'm totally windows noob & ignorant)