Preheat the oven to 350°. In a large nonstick skillet over medium-high heat, warm the oil until hot but not smoking. Add the onion and garlic and saute until softened, 3 to 5 minutes.
Add the bell pepper and jalapeno pepper and saute until the bell pepper is softened, about 3 minutes. Stir in the tomatoes, lime juice, chili powder, oregano, and salt, and bring to a simmer.
In a 2-quart casserole, stir together the beans, rice, and half the scallions. Pour in the tomato mixture and stir to combine.
Sprinkle the casserole with the cheese and bake for 10 to 15 minutes, or until the rice and beans are heated through and the cheese is bubbly. Sprinkle with the remaining scallions and serve.
