Is it possible to compile C programs in Net Express? If so how would Net Express need to be configured?

It is possible to do this. For a program having the .C extension, Micro Focus Net Express build will compile using the CL.exe command, please note that this has to be set in the Environment Variable PATH. The Cl.exe file is the C compiler that is ships with Visual Studio 2008 and is usually found in this location:

C:\\Program Files\\Microsoft Visual Studio 9.0\\VC\\bin\\cl.exe