Lets start by seperating terms, ESC and BEC. Most but not all ESCs (Electronic Speed Control) have a built in BEC (Battery Elimination Circuit) you can also buy a stand alone BEC that is not an ESC. The one you have posted contains both circuits.
All that said, unlike Piper Chuck, I do not know of any receivers that require 6 volts so I will have to take his word for it. Double check before buying.
We can't recommend a receiver until we know what airplane this is going in and what transmitter you will be using. ie... if it is a small park flyer you will want a micro receiver...