Using current version of the server - you can see that there is no OAuth managed or published API endpoint for canvas delete (screenshot 1). However this API does CLEARLY exist as you can see if you inspect what happens when you hit the delete button (screenshot 2 clearly shows the API being called - but it requires user login security token)
Please can you enable this API for OAuth - the API already exists, it just needs to be exposed with the others.
CC: @BlytheE