What does Falun Gong think about life after death?

Your spirit continues to exist in a subtler dimension without the coarsest of your many bodies - the physical body; it's like you've shed your outermost skin. After some while, when circumstances are correct for your further learning and being tested by life on Earth you will reincarnate, unless you have cultivated to consummation, in which case you won't have to endure the limitations of the flesh body again. This Earth of ours is seen as a correctional facility of sorts where you have to cultivate a good heart and pure mind amidst all the strife of society to be worthy of parole.

That is my understanding and Wording as I was too lazy to seek out a definitive answer from the books.

If you are really interested, try reading Zhuan Falun.