Add the rest of the ingredients and simmer gently until tender. Add salt and pepper to taste.
Remove chicken legs from the pot and when cool to handle, remove and discard skin (this step is optional, you can keep the skin if you like).
In the same skillet, on medium heat, add 2 tablespoons butter and sauté the onion until translucent. Add the rice and stir for two minutes (or less if the onion starts to brown quickly). Add 1 cup of the warm stock and reduce heat to a gentle simmer. Continue adding the stock, half a cup at a time, stirring quite often.
After you have added about 6 cups of stock, add the parmesan, lemon zest and salt and pepper to taste.
Serve on plates, add on top a chicken leg and sprinkle with red pepper flakes, sea salt flakes, some fresh oregano and a slice of lemon. Eat.
Keep in mind that in risotto recipes you can't always have exact quantities for the liquids required. The amount will vary depending on the type of rice, amount of heat and other factors. You should always use your eyes and taste to determine when it's ready.