The apps inside assetto corsa are generally bound within the window where AC is updating the screen. The only way to get apps onto a second screen would be to run AC in "windowed" mode (not fullscreen) with a custom resolution and then adjust the AC output window so that it was being drawn on both screen. This may result in a hit to your FPS (not sure about that, exactly, but I think windowed mode is not as efficient as running fullscreen in terms of FPS). I think there are some "apps" that will show data from within AC on a webpage (that you could view in a browser or tablet or smartphone), so that would also be an option, but may not have all the data points or graphical displays you're looking for.