Managed code doesn't use a linker. The C/C++ equivalent of a reference assembly is the #include directive, you need that in C/C++ to allow the compiler to generate code for an external type. Exact same thing in C#, you can't use an external type unless the compiler has a definition for it. The reference assembly supplies that.
The equivalent of C/C++ linking is done at runtime in a managed program. The JIT compiler loads assemblies as needed to generate machine code.
One thing you can do in a C# program that you can't do in a C/C++ program is using Reflection. It allows you to invoke a constructor and call a type's methods with type and method names as strings. Start that ball rolling with Assembly.GetType() and the methods of the Type class. However, consider a plug-in model with, say, the System.AddIn namespace first.