In Mortal Kombat 9 (2011 version) for the PS3 and Xbox 360, each character has multiple fatalities that can be performed at the end of the match when your opponent is defeated.
This is the list of all finishers (two fatalities, one babality, and one stage fatality) for Liu Kang.
All of these moves can be unlocked and added to your moves list by performing them in either Arcade Mode or Versus Mode.
Check out these complete fatality guides for more finishing moves:
Fatalities and babalities for Mortal Kombat on Xbox 360
Fatalities and babalities for Mortal Kombat on PS3
Liu Kang’s Fatalities & Finishing Moves
Xbox 360
Fist Of Flame — Forward, Back, Down, Down, A while in sweeping distance
The Beast Within — Down, Down, Forward, Down, B in jumping distance
Babality — Down, Down, Down, B in jumping distance
Stage Fatality — Down, Forward, Back, A at close range
PS3
Fist Of Flame — Forward, Back, Down, Down, X while in sweeping distance
The Beast Within — Down, Down, Forward, Down, Circle in jumping distance
Babality — Down, Down, Down, Circle in jumping distance
Stage Fatality — Down, Forward, Back, X at close range