If you still get numb hands after you make sure your saddle is level, move your saddle back. This will shift weight off your hands and onto your butt. You may have to lower the saddle just a bit to get the same leg extension, and you my have to flip your stem up if it's down, or if it's already up, raise it and/or get a shorter stem.

If your fit is already good or close to it, you shouldn't have to move the saddle much to shift a good amount of weight off your hands.