What kind of tool do you use to push the caliper piston in a 2006 toyota tacoma?

It depends on whether the parking brake is on that wheel. If not, a clamp or vise with a socket will do it. If the piston has a groove or X on it, which normally is the case when parking brakes are attached, the piston screws in clockwise by getting a tool in the groove. Needle nose pliers will often work in a pinch.