In a saucepan, bring water to a boil. Add rice and stir. Reduce heat, cover and simmer for 20 minutes. Remove from heat and chill.
In a large bowl, mix together the rice, beans, tomato, cheese and green onion.
In a small bowl, whisk together the oil, vinegar, peppers, sugar and salt. Pour over the rice mixture and toss to coat. Cover and refrigerate salad for 30 minutes. Top with avocado just before serving.