Create a REST Screen on a Flow.
That Screen does not allow to drag any widget (its a empty page).
On that Rest Screen i can create actions that map to a Action on a Rest Api.
The URI translates on the API for .../<ScreenName>/<ActionName>.
The platform haddles the secutity, handles the JSON serialization.
With the REST Screen, we can implement one api that JQuery plugins and javascript integration can be done easy.