The .NET is only good for the user interface. As I could see in your link it does it by using wxWidgets.
You can forget about the windows messaging and API to interract with paltalk on the Mac though.
If anything can be done, it would have to be done on a Mac machine with a Mac programing envinronment I believe, and you’ll need to learn the windowing system Mac is using, and probably C or C++ I don’t think they have basic for unix LOL.