nanoFramework.CoAP is a lightweight library for building CoAP enabled applications that works with .NET nanoFramework.
The samples are located in "nanoFramework.CoAP.Samples" project. This project contains several samples and basics of usage of nanoFramework.CoAP library.
Also from the following link you can download free eBook describing what is CoAP and how to use it on IoT devices with .Net nanoFramework and nanoFramework.CoAP library.
http://idaax.com/download/free-ebook-on-coap/
Acknowledgements
nanoFramework.CoAP is based on a code base from CoAPSharp project.