Spray a frying pan with a non stick cooking spray or coat with butter. Set aside.
In a medium mixing bowl, whisk 4 eggs and 1 Tbs milk together (make one omelette at a time, then repeat this step once first omelette is done).
Add eggs to heated pan.
Cook over medium/low heat.
Flip over and cook other side.
Once flipped over, add a couple heaping spoonfuls to black beans on one side of the omelette and spread over 1/2 of omelette.
Add some cheese.
Fold omelette in half.
Flip over one more time so cheese melts.
Once cheese has melted, add omelette to serving dish, add more cheese, and top with remaining ingredients.
Repeat with the remaining eggs to make another omelette.