Place the rinsed beans in a large mixing bowl. Mash with a potato masher until they form a paste. Add the rice, cumin and cayenne. Stir to combine and taste (just to determine if spicy enough). Add the egg and work with your hands or a large spoon to combine well.
Use a small scoop or a spoon to form the balls and then gently round them with your fingertips. Form all of the balls and place them on a large plate or cutting board. In a large skillet over medium high heat, warm about a tablespoon of oil. Cook the balls in the skillet, until they are lightly browned on each side. This took a couple minutes on each side, turning them 2-3 times each.
If you aren't familiar with cooking things in batches, here is a tip.
Start placing your rice balls in the pan, at the outer edge, next to the
handle. Go clockwise around the pan and then fill in the middle. It is
easy to remember which ones have cooked the longest that way and by the
time you fill in the middle, it is time to start flipping them over and
continue around the circle again.
After the balls are browned, remove them from the pan and place them on a clean plate. Tent loosely with foil to keep warm. Cook the remaining half of the balls and then serve warm. Enjoy!