Fighting technique?
No.
To be more precise, martial arts would be the better term.
Flying leaves, this skill had appeared in the ancient martial art novels. This skill had been worshipped by many and regarded as a godly skill. However, even in the origin ability era when one had reached the limit of physical fitness, people still found that it was impossible to master this skill.
Flying knives?
They could do that!
It was possible because a flying knife was built using metal. With the current physical fitness, extremely quick reaction, and powerful force to hit a target wasn't difficult. However, to make it into a one-hit kill weapon was just a myth.
But…
Dead leaves?
Leaves themselves were unusually fragile. Just a little force and they would be destroyed. If they were thrown at full force, most of the leaves would probably have been destroyed before they hit their target.
To perform this flying leaf skill perfectly…