How to do it, with no image editing software or screen shot:
First, hide all the icons on your desktop and take a wide angle photo with your hand in front of the screen, making sure that the edges of the monitor and beyond are visible. Make that image your desktop wallpaper background. Then, place the icons back onto the desktop and open a small window and place it where your hand is on the screen. Lastly, take another photo of your monitor, but this time just zoom in so that the frame of the monitor is not seen.