Basic Pen Tool
This tutorial is very easy and can definitely be translated into any program.
First, create an image and make a new layer.
Select the pen tool and change yor settings to mine
Randomly scribble around or draw what you want and then release the button. The path should fill in with the selected color of your choice. See mine.
Now, right click and rasterize the layer. Now you're done! :D This is my