With the recent announcement of the Public Preview of Azure Service Fabric, I've been building some test applications for it.
Once you deploy your application to the Cluster there are multiple ways to delete individual services, actors or the entire application.
You can use the Service Fabric Explorer or the Cloud Explorer from within Visual Studio.

At this point in time, there is however still no option to delete an entire Service Fabric Cluster.
The only way to delete the entire Cluster is to delete the Resource Group the cluster is created in.
So for now :