The special powers of the left and right eyes of uchiwa look like being antagonists.
Amaterasu: left fires the right absorb.
The kamui of kakashi ( left eye) creates a clockwise whirlpool, the whirlpool created by tobi ( right eye) turns in the opposite direction.
One (left) sends the dimension hidden in the reel a short moment has the place it looks (as the flames of amaterasu), the other one absorbs the reel in this dimension beyond the eye a short moment.
What quantity of reality can he absorb? Why he needs to touch the thing which he wants to transport , maybe he doesn't need contact .