There has been a recent forum post that resolves your question, so check that out for the complete solution.
In essence you listen to the touch event (that phonegap dispatches) and then you trigger an artificial key event that Twoway will respond to.
You can trigger the artificial key event globally:
Crafty.trigger("KeyDown", {key: Crafty.keys.UP_ARROW});
or if you have the reference to the player entity:
playerEntity.trigger("KeyDown", {key: Crafty.keys.UP_ARROW});
I do not know how phonegap dispatches touch events though (the solution in the forum post uses Hammer.js for listening to touch events).