Southwestern Rice and Black Bean Salad

1 1/2 to 2 cups cold cooked brown rice
one 16 oz. can black beans, drained and rinsed
1 1/2 cups cooked fresh corn kernels (from 2 medium ears) or frozen corn, thawed
1 medium red bell pepper, cut into narrow 2-inch strips
1 medium firm ripe avocado, diced
Juice of 1/2 lemon or lime, or to taste
2 tablespoons extra-virgin or light olive oil
1/2 teaspoon dried oregano
1/2 teaspoon ground cumin
2 tablespoons apple cider vinegar
season to taste

Combine the rice, beans, corn, and bell pepper in a serving container. Toss the avocado with the lemon juice, then add to the rice mixture along with the remaining ingredients. Toss to combine. Serve at once or cover and refrigerate until needed. Cilantro or scallions can be added.
From The Vegetarian Family Cookbook