Specifications of a motor which will light an led (momentarily) from hand-spinning?
A motor is a backwards generator. So flip all the specifications around.
That motor has a no-load RPM of 13500RPM when 6V is applied. So for you to get it to produce 6V, no-load, you must spin it at 13500RPM. Spin it at 1/3 the speed and you will produce 1/3 the voltage. Can you pull that off manually? Probably not. Pick a motor that spins the lowest possible speed at the highest possible voltage.
You are going to a bigger motor, since bigger motors have the tendency to run slower for the same voltage. If you have 6 diodes to make a 3-phase rectifier, an outrunner motor is your best bet (it is a brushless motor so has no brushes to rectify the current in the coils to DC. It will end up as 3-phase AC so you need a 3-phase rectifier).