What tool can get the Technic pin out from a connection closed in the other end?
Push the Technic pin in a beam hole, then insert a rod (antenna or minifig tool handle) into the hole in the pin from the other side. The rod will prevent the "lips" of the pin from closing in, therefore preventing the pin from leaving the beam. Then you can pull on anything attached to the other end of the pin.

This example below shows the removal of a pin from a beam: