V6 API: does the oauth token request require user interaction?

All of the documentation I'm reading suggests that end-user interaction is required in order to get the oauth token. According to this page, it looks like the end-user has to explicitly click a button allowing the application to work. Is that so? If it is, that's a non-starter: my specific mandate is one-click sending of documents for signing from our internal application. Opening another URL to grant access isn't going to fly.

Is there a purely programmatic way to do this?