Single click (finger tap) is the most appropriate hover alternative on touch devices.
- http://www.freepatentsonline.com/7877707.html describes a method for detecting and interpreting real-world gestures on "touch and hover sensitive devices.
Touch devices are developing their own distinct set of user expectations. Touch to hover is perfectly acceptable.
Some touchscreen technologies do support hovering. For example, with Microsoft Surface and some specialized tablet displays distinguish between hovering and pressing.
Examples of real-world gestures include "OK gestures," "grasp everything gestures," "stamp of approval gestures," "X to delete gestures," and even "hitchhiker directional gestures." The patent also includes a description of a security feature where users are asked to draw personalized gestures to gain access to a device.
Gestures for hover sensitive devices would include gestures that multi-touch only devices would be unable to detect. The "OK gesture," for example, is not flat, so a multi-touch sensor panel would be unable to register it as touch input.
According to the application, capacitive touch sensors can already detect nearby hovering as a "weak" touch. The addition of proximity sensors would improve the range and resolution of hover detection.
Resources
What are some alternatives to "hover" on touch-based devices?What are some alternatives to "hover" on touch-based devices?
iPad/iPhone alternative for hover statesiPad/iPhone alternative for hover states
Re-thinking "hover" functionality with touchscreens in mindRe-thinking "hover" functionality with touchscreens in mind
Implementation Example