Well, basically any instant death situation kills the Jedis.
1) Bottomless Falls.
2) Kill zones, like the back of Endor Generators, Sarlacc pits, carbonite pit, etc...
3) Out of bound, for a long time.
4) Being landed... this pushes the target into the floor basically, and death.
5) Running target over by high speed vehicles. Sometimes things only pushes characters aside(like AAT) So speeders with "forked" front is better.
6) Ram them thru the walls, its the same as getting fall killed during wall hack.
Lowering the counter works obviously, but I have yet to blast them to death. Their health is basically infinite from what I see. Not sure if you can inflict huge amount of damage before the healing lights goes up though, but making the hero trip would certainly activate the healing.