Just run in a window of the required size (to fill more than 1 monitor), with decoration turned off. When the window be on top, it will look like what you need. Here’s info on how to turn off the decoration: Turning off Frame decoration for a windowed mode - #2 by normen (i am sure you can figure how to run in a window of big size and position it correctly by yourself, it’s pretty basic, but do not hesitate to ask if you have more questions)