I'm currently working on a RFC connection between Visual Studio 2017 and a SAP Server hosted on Linux (openSUSE) on a VirtualBox. The only posts I found about this problem are very old and not helpful. I want to create a RFC Function in C# that returns the data of the database in a chart, but I have no clue how to start with the code and how to setup the connection between my Visual Studio and the SAP server. I hope someone can help me with these problems.
If you have no clue how to start, then why not first having a look into the NCo documentation? You can download it from https://support.sap.com/nco.
Since your environment does not seem to be limited to Windows only, I would also think about if the .NET environment is the best choice for your project? You will get better OS portability options if using other connectors. You will find the SAP connectors for other environments and programming languages at https://support.sap.com/connectors.