You'll need one to adjust the windage (unless you want to go with a brass drift punch and mallet).
For elevation you can use a makeshift tool.
I have the standard square type that looks like a small clamp and has the elevation adjustment cut into the handle.
Not that it really matters, but what type of AK?
If it's an older WASR there's a chance that the front sight is canted and no amount of sight post adjustment will correct it.
However... there is a fix for correcting the cant...
http://www.gunsnet.net/Linx310/gascantfix.htm
Reason I ask is that on two of my home builds (as in old, used parts), the front sight was a real PITA to move even with the tool and a set of vice grips.
If it's tough to move, apply a bit of Kroil or penetrating oil to the sight and let it soak in.
Unless the windage is really off, I wouldn't even be that concerned about it.
After all... it's an AK, minute of barn door is the norm.