Technically not hand-held, but it is a one-handed weapon.
Aiming is intuitive and precise, and the signal to fire is unambiguous.
How it works: An onboard computer infers the line of sight from the position of your eye and the position of the fingertips the moment they touch. From there it is simple to solve for the correct line of fire, adjust a servo-mounted weapon, and shoot. And as you can see from the second image, the trigger mechanism allows for a quick rate of fire.