In this thesis, we present and evaluate CountMarks, a multi-touch marking menu technique designed for use with mobile head-mounted displays. CountMarks extends conventional marking menus (gesture-based radial menus) by using multi-finger input on a mobile phone screen. We discuss the design of two variations of CountMarks, exploring selection efficiency, public acceptability, and ergonomic comfort. We conduct two studies: the first compares CountMarks to a traditional marking menu. Our second study evaluates CountMarks while standing and walking and with interaction occurring on hand-held and leg-mounted devices. Our results show that CountMarks makes faster selections and allows for better search accuracy than marking menus, and can be used in the hand while standing or walking. Finally, we present an application demonstrating the implementation of CountMarks in an existing user interface and we suggest direction for future work.