Microsoft's C# compilers compile source code into MSIL, which runs on the
..NET Framework (or another CLI-compliant engine). What you'd need to
accomplish your question is a C# compiler that generates native code for the
processor. I'm not sure if any of these have been built by 3rd parties,but
it is possible.
So, if I wrote a C# app which did nothing except display an empty form
with the caption "Hello World", how big would the EXE file be, if
linked as a stand-alone app?