We have watched Flash season 2 and know Jay Garrick is Earth-Two Flash and Zoom is the villain blah blah blah... Yet the question remains, who is Zoom? Oh Yeah by the way, thank you CW for not showing Zoom's face in like the 7th episode like you did for Reverse-Flash in season one. (No sarcasm)
I have watched the episode "King Shark" and I know that Zoom is unmasked. The guy who is under the mask is a guy that looks like Jay Garrick. Here is the clip:
The first thought I got was that he must be Hunter Zolomon. But Hunter Zolomon is from E-1(Earth-1).
Here is my CRAZY explanation for this:
Flash(Wally West) is fighting Zoom(Hunter Zolomon). Let's take a little sidestep here.
If you don't know, in comics Hunter Zolomon is a friend of Wally West then he gets the power to travel in time so much that he can basically have super speed. Thus, becoming Zoom. Soon he becomes the enemy of Wally(Flash). He becomes the enemy so he can make Wally faster and better.
So, anyway, now that we are past all that, let's get back to my story. Wally is from the time that Barry is from, he is the son of Francine.
One day Zoom is fighting Wally. They both try to defeat each other yet fail. Zoom finally kills Wally and goes so fast he boosts back in time. Instead of jumping to that time in E-1(where he originates from), he crashes through time and goes through one of the breaches from which Zoom comes into E-1. Going through the breach he still goes back in time and finally lands in E-2 a year before the Particle Accelerator explosion.
Zoom has no powers. He goes mad. He learns what happened and realizes there is going to be a Particle Accelerator and he could get actual super speed this time, the way Barry Allen did. So he bides his time. He makes a living. Creates his evil lair, makes his suit look like a demon. And stays in the vicinity so that when the Particle Accelerator explodes, he gets speed. He learns about a Flash then he makes his ultimate plan, to steal every Earth's Flash's speed so he can be the fastest and ultimately dominate every world. He becomes so fast his lightning is blue. (By the way, this Zoom has a black suit ever since he gets his powers for the 1st time). This theory is complex because CW is complex.