When it comes to creating art to use with your CNC Plasma cutter there are tons of options for you to choose from. You can spend lots of money trying all the wrong ones, or you can start with the industry leader Corel Draw X6.
When it comes to plasma art there is no better fit. The features are awesome. CorelDraw has a low learning curve compared to others as well as having a low price and great support.
Having a great program and knowing how to use it are two different things. Corel Draw is an industry standard and you will find thousands of online tutorials that will walk you through the different options and get you going quickly.