At the beginning of the movie, Vader and the storm troopers board Princess Leia's ship. At one point Vader was holding a rebel in the air and was interrogating him, and then throws him away after he died. I was somewhat confused as to how that rebel died. Did he commit suicide, did Vader crush his throat, something else?
The man that Vader is strangling is Captain Raymus Antilles. He's the captain of the ship carrying Leia and the droids. His death was by strangulation by Vader during that scene.
You can read about him here.