Here's a full C# wrapper for the Zendesk REST API: https://github.com/eneifert/ZendeskApi_v2. The readme contains a list of all the public methods, but hopefully it will be simple to use. The code is of course open source, so feel free to add or make whatever changes you like.
If you aren't familiar with GitHub, visit their help page.
Enjoy and feel free to ask questions.