1.Is not possible to do this, because the web application is running on the web server and only the web application's clients are running in web browser, and desktop application is running on your computer. Also there is no redirect in the context of desktop application.
2.What you can do, is to open a web browser for your given URL directly from your desktop application, like in the example below:
string url = "http://www.codeproject.com";
System.Diagnostics.Process.Start(url);