Thank you for the video, I watched it, these are my considerations.
First of all I think you're using the Leap Motion Controller almost at the threshold of the maximum distance to use, so I would recommend you keep the hand closest to it, you should also try to make the finger movements slowly, so as to have greater awareness of the mouse button pressure / release, especially in a first use.
Another thing to check is the frame rate with which it is working your Leap Motion Controller, and that also depends on your specific PC setup, you can check this by opening the visualizer of Leap Motion, and by pressing the button h. You should have about 100 fps to get good results using the controller.
I hope that these informations will be helpful for you.