Detect face on WebCamTexture and hit it

Hi people,

I am very new to Unity3d and I need your help about the way the things work. I am trying to make my Android app which will use device camera, detect (or track) the face and then throw something on it. I think there is something similar on PlayStore where you have a rifle and toy can shoot people around you (I want something similar).

I succeeded in setting WebCamTexture on RawImage and it works fine. But, could someone give me some hint or link where do I start looking for how to shoot some point on that image? It should take in consideration distance to the target (if it is even possible).

I suppose this may be stupid or trivial question, but I am totally new to all of this.