The hand with it's five fingers spread is used in many cultures. In ancient Native American culture it was perhaps used in rituals for preparing for war. In Arabic and Jewish cultures it is said to ward of the 'evil eye' and is often found with an eye in the middle of the palm. It's sometimes called 'the hand of Fatima' after prophet Muhamed's daughter, or 'Khamsa' meaning five.
Evidence of it's use as a symbol to ward of evil can be found all over Libya. As a simple palm print on a wall like the one in the photo, or in more elaborate, stylized charms and emblems. On houses, vehicles, and in businesses as well as on keychains and jewelry, khamsa abound in Libya and north Africa and the Middle East.
In modern times the palm has meaning too. People often greet one another by slapping an upraised palm against that of another person, called 'high five'. It's also used as a gesture of congratulations, elation or victory. A modern gesture that has spread throughout the world.
I greet you... High Five!