Our OAuth API documentation notes that OAuth requires a key and secret set at the account level. Unfortunately our free accounts don't allow you to create those.
If you decide to use the open source version of Canvas, you'd be able to have access to the account level and create them. More info about that can be found in Home · instructure/canvas-lms Wiki · GitHub.
FFT accounts do offer authentication through other social methods (Twitter, etc.) if that's also an option for you.
Let us know if you have any other questions!