Heat the olive oil in a medium saute pan. Add the onions, garlic, and salt and cook on medium-low heat, stirring, for 5 to 10 minutes, until the onions are tender.
Add the bell peppers and cumin and cook for 5 minutes more, until the peppers are soft, stirring frequently. Remove from the heat and set aside.
Thoroughly mash the beans by hand in a large mixing bowl. Combine the parsley, rice, and lemon juice with the mashed beans. Add the cooked vegetables and mix well. Add black pepper to taste.
Shape the mixture into 18 small patties, about 2 1/2 inches across. Prepare a large skillet with a coating of oil. Heat the skillet and cook the patties on medium heat until golden brown on the underside, about 5 to 10 minutes. Gently turn them and lightly brown the other side, about 5 minutes longer. Serve hot or at room temperature.