It would be good to have a Spotify Tile like you get on android Widget for playing music permanently on-screen.
Direct API Tiles are discussed in a few Feature Request Topics; but such a concept is not on short-term radar.
More details are prominent in this Topic: http://support.actiontiles.com/topics/1285-deeper-richer-kodi-control-tile/
At the moment, a community member has provided this KB Article:
Using a Shortcut Tile to trigger Spotify Playlist
Virtual switch + Tasker
I have a play list start playing when I run a certain routine and did away with the virtual switch
I was looking for a small inbedded Tile not a link to open another window
Customer support service by UserEcho