Chief table pounder
A chief table pounder is the most ardent champion of a new or different way of doing things. They emphasize their points by slapping office furniture (usually a board table) with an open palm, similar to a judge using a gavel to impose order in court.
To show conviction to colleagues, they use palm-down gestures to emphasize key speaking points. Without actually striking the table, they pronate their open palm—flipping it down parallel to the table's surface—and proffer it as a sign. Reaching the gesture forward and moving it up and down like a baton helps drive home their most important ideas. Listeners, often without realizing why, will sense the speaker has greater confidence.