In terms of accessing the docker socket from your application, if you have strict confinement for example on Ubuntu, you need to use plugs: [docker] in your snap app, and then connect that plug to the slot that the docker snap exposes. You can’t communicate with a non-snapped docker from inside a strict snap. After doing this you will need to request permission via the #store-requests category for usage of the docker interface. See Request use of docker interface [Was: Classic confinement request: Dunner] for an example of this sort of request.
Also it appears that the tidal snap doesn’t declare any interfaces, so you will want to at least declare some interface plugs like network, etc. for your snap to work on Ubuntu or other distros which do have full confinement.