Because they can be fairly expensive, I usually buy the biggest can of green chiles I can find and then wrap them in Saran in portions sizes and then store in a freezer bag. One of my 'portions' is used for chopping off chunks of chile when I want some to chop for a recipe.
To make the fried green chiles:
Drain the chiles and dry them on a paper towel. Prepare a mixture of about half flour and half corn meal to which you've added salt, cumin & cayenne pepper to taste.
Open the chiles...don't worry if they tend to come apart on you...it happens...and place the cheese. You can use whatever cheese you like. I used this today to show you the amount of cheese needed. For these 4 chiles, I only used 1 slice of cheese. If you use too much, you will have an oooey-goooey mess in your skillet.