First, there is no English word "tooking" at all. The verb form is "taking." Second, the first sentence is better, but I would say, "My hands were shaking as I took them." I can't really explain why on that one. It just sounds better to my ear. "When" is not wrong, and if you said it that way, no one would correct you. But just for the sake of learning, "as" has a better ring to it. ("has a better ring to it" = "sounds better")

My hands were shaking when I took them.

My hands were shaking AS I took them. "When" is not correct here.

first