This is a feature that is already available in Microsoft Remote Desktop for iPad and it works very well.
There are two modes for touch input, and you can switch between modes at any time:
Mode 1: Use touch to click on anything on the screen, so for example in this scenario:
Right click a file and delete it: Touch on the file with hold, once context menu shows up, touch on delete.
Mode 2: Use touch to interact with mouse cursor which always shows in the screen. So in this scenario:
Right click a file and delete it: Drag one finger across the screen to simulate mouse movement until the cursor reaches the file you need to delete, then press and depress instantly with two fingers (can be done anywhere in the screen as your touch won’t move the cursor away from the file). Finally drag one finger so the cursor moves to the delete option in the context menu, then touch with one finger to simulate click on delete.
Mode 2 is much more useful on iPad when you are not using physical input devices because it is easier to do tasks that require more precision, like resizing a window, clicking in areas / icons / options that are very small, dragging cursor across multiple files.
It will be really useful to have this mode in Shadow App for iPad.
PS. You can try it yourself anytime if you download the Microsoft Remote Desktop App for iPad and connect to remotely to any Windows PC