I created wrongly 2 times the same app on developers.vimeo.com. My goal was to create the new one on a new account and then delete the old one from the first account, but, due to a monster bug on vimeo login, I logged with my second account and finished logged with the first one. ... but this is not my question.
The simple question is: what's the right path to delete a existent app ? We can't find a delete button on the developer panel.
Currently, it is not possible to delete API apps created on your Vimeo account.
However, there is no limit to the number of API apps you can create, as long as you follow the Developer Guidelines (https://developer.vimeo.com/guidelines).
That said, if you would like your app manually deactivated, you can always reach out to Vimeo support for further assistance- https://vimeo.com/help/contact.