To get Peng you must be on the flight deck on Chapter 11. When in the flight room where your ship "used" to be, look between the walkways. It is in the gap between Runway 1 and 2 by the shuttle in the Flight Hangar. You should see a very small statue that has a golden appearance. Pick it up with kinesis and you will receive the Peng treasure (and its achievement or trophy). It can also be sold for 30,000 credits.