PWS currently support .NET Core applications, which run on Linux. However, PWS does not support .NET Windows applications at this time. There is no command line that would enable Windows stack.
We don't offer .Net on PWS. Before we can offer .Net on PWS, we need to wait for Windows Server 2016 to provide sufficient isolation in .Net environment. There are plans to turn that on. The isolation for windows apps is not sufficient to run a public cloud.