I'm the creator of those video
To make a laser it's very simple. You must create a laser with photoshop in an image like 100px*3000px
Apply an Add effect.
Then you can rotate him...
So, do you make a big one, or stretch it?
You can make a big one and rotate it and count on your foreground to 'block it out' as its rotated. Or, you can have one with a set base size, calculate the distance to its 'target', stretch it along the X axis by that size, and then rotate it in that direction. The latter is what I do.