Well ... if you run X and start cgminer in a terminal window it already uses it
However, having a display (in my case) 110 times the size of the RPi and using probably 100 times the power seems rather pointless
indeed, even the 7" displays feel a bit overkill.
btw - what powered USB3 hub are using with Pi?
A no name brand one made in china: ID 05e3:0610 Genesys Logic, Inc. 4-port hub
I can get it to mine fine on the RPi with the Jalapeno and the Blackarrow Lancelot.
Fails to mine (but detects the devices OK) with an Icarus and an Asicminer USB.
Still got a few more ideas to try yet.
It works fine on my desktop with all mining devices I have, so I'm not sure which one of a list of possible causes it is yet.
My powered USB2 says it is Belkin, but it is clearly related to the no name one:
ID 05e3:0608 Genesys Logic, Inc. USB-2.0 4-Port HUB