Use items in No Man's Canyon was a mission in Jak II. This time Jak had take the three artifacts from the Mountain Temple (the Gear, Lens and Shard) and use them to activate an old Light Tower at No Man's Canyon. This revealed the location of the Tomb of Mar to Jak and the Underground.
The PlayStation 3 and Vita versions of this mission are related to a trophy named "No Man is a Canyon", completing this mission will reward you with a bronze trophy.
Once at the Mountain temple area and taking the elevator down there will be a light beam at the bottom. Approach and in a cutscene the Seal of Mar unlocks the precursor door, allowing further passage. Next is a large bottomless pit with three grind rails interrupted by some sort of precursor object. Grind down the rail and make sure to jump over the object onto the next rail. At the other side take a left and go through the canyon to view a cutscene.
To get back to the city go back to the pit and instead of taking that left earlier take the right (in this case forwards). You'll end up back at the starting area with the warp gate.