He pinched up a small amount of tea leaves with his fingertips.
Tips
usage
撮 as a measure word always refers to tiny amounts taken between the fingers: 一撮盐 (a pinch of salt), 一撮头发 (a tuft of hair). As a verb it means to pinch up or gather. Not to be confused with 撮合 (cuōhé, to bring together / matchmake).