You really don't want to zoom the page at all. That won't accomplish what you want. You need to tell the mapping library to zoom, which is not a simple image zoom, but will load more or less detailed tiles as needed.
You would need to add event callbacks to catch the gestures you want to use, and make calls to the mapping library.
Dunno about OpenLayers. jquery.ui.map (which, despite the name, also does work with jQuery Mobile) does this for you for Google Maps V3.