In a small pot over high heat, add 2 cups of water to the rice and bring to a boil. Cover and turn heat to low. Cook until rice is tender and water is absorbed.
While the rice is cooking, add the oil to a skillet over high heat. Add the garlic, onions, red bell pepper and corn. Turn to medium heat and sauté until onions are soft and the corn is no longer frozen.
In a large bowl, roughly mash the black beans with the back of a spoon. Mix in the rice and then the cooked vegetables.
Add the salt, cumin, chili powder, cayenne pepper, and tomato paste then stir well.
Divide the mixture roughly in half and blend one half with an immersion blender.
Re-mix the two halves along with the breadcrumbs and egg white.
Using your hands, make 8-10 patties.
In a non-stick skillet, heat the burgers over medium heat for 6-7 minutes on each side.
Notes
I blend half of the mixture to make the patty less chunky. You can choose to blend all of it or none of it according to your preferred texture.
When freezing, lay wax paper between each patty. You can thaw them in the microwave for 1 minute at 50% power.
When cooking, do not be tempted to remove or flip the patty early. It needs to thoroughly cook so that it holds together and the egg cooks.