Heat the oil in a large saucepan or pot over medium heat. Add the onion and bell pepper, sprinkle with salt and pepper and sautéed until the onion begins to brown, about 5 minutes. Add the sausages and sauté until beginning to brown, about 5 minutes. Add the cumin, coriander, chili powder, and red pepper flakes. Cook until the spices are fragrant, about 1 minute. Mix in both cans of beans with their liquid, tomatoes, and 1½ cups water.