Understanding that Power Tools are integrated to the main body of EF6 - where is the interface to fire a 'Reverse Engineer POCOs' from existing database to be found?
PowerTools are not integrated with the EF6 designer at the moment. Since it did not fit in the release we are thinking about updating PowerTools so that they work with EF6 until the inegration with EF6 Designer is complete. For reference, here is the work item we use to track this work.
PowerTools Beta 4 now supports EF6. See this blog post for more details and the link to the download.
I suggest the Entity Framework Reverse POCO Generator plugin for VS 2013. It seems more user-friendly in the configuration, and less chance of overwriting your custom templates.
There is also a 30 minute video on the page showing how to use it. However you may fall asleep at the relative monotone sound. You should be good to go with the first 5 minutes.