Cook the rice like according to the instructions on the packaging (see Tips)
Meanwhile, heat the oil in another pan. Finely chop the onion and garlic, then cook for 5 minutes until soft.
Finely chop the tomatoes. Trim the spring onions and slice them diagonally.
Add the chilli powder to the onion and half of the chopped tomatoes, then cook for 15 minutes until the tomatoes are soft.
Add the black beans and the mixed beans in chilli sauce. Warm through, then turn off the heat.
Peel and slice the avocado.
Transfer to serving plates. Spoon over the tomatoes and beans, then top with the remaining tomatoes, the avocado and the spring onions. Season to taste and serve, scattered with the chopped coriander.