In a medium saucepan, combine quinoa and water or vegetable broth. Bring to a boil, then reduce the heat to low, cover, and simmer for about 15 minutes or until the quinoa is cooked and the liquid is absorbed. Fluff with a fork and let it cool.
Prepare Ingredients:
In a large mixing bowl, combine the cooked quinoa, black beans, diced mango, diced red bell pepper, chopped green onions, and chopped cilantro.
Make Dressing:
In a small bowl, whisk together lime juice, olive oil, ground cumin, salt, and pepper.
Combine and Toss:
Pour the dressing over the quinoa mixture and toss everything together until well combined. Adjust salt and pepper to taste.
Chill:
Refrigerate the salad for at least 30 minutes to allow the flavors to meld.
Serve:
Before serving, garnish with additional cilantro and avocado slices if desired.