Hi Ravi,
all you need to do is create a module pool program with all the required functionalities that you want - create screens with dimensions 16*20 for RF gun devices, keep the layout as simple as possible, add as many screens as you want to avoid pop-ups (as the original device is already small). That way, the editing and onClick functionalities will automatically be taken care of.
Blog: Internet Transaction Server (ITS) mobile - Developing ITS templates from scratch
All you would have remaining to do is make it look neat using CSS and make changes in the HTML templates that are generated from the module pool program screens.
Blog for styling: ITS templates – Styles, Themes and Legibility (MIME Repository)