Heat a skillet over medium heat, and coat with cooking spray. Add cooked rice, 2 tablespoons ketchup, ham, and cheese, if using. Cook and stir until ingredients are well combined and heated through, about 8 minutes. Scoop mixture onto a serving bowl and shape into an oval.
In a bowl, beat eggs and salt and pepper. Heat a small skillet coated with cooking spray over medium heat. Add egg mixture; cook over medium heat. As eggs set, lift edges, letting uncooked portion flow underneath. Use a spatula to gently fold eggs into a cocoon shape. When eggs are completely set, remove from the heat.
Place omelet on top of rice and run a knife length-wise through the top layer of omelet. It should open like a butterfly and drape over rice. Top with final tablespoon of ketchup and a sprinkle of parsley.