In a medium saucepan, bring 2 cups of water to a boil. Add the rinsed quinoa, reduce the heat to low, cover, and simmer for about 15 minutes, or until all the water is absorbed. Remove from heat, let it sit covered for 5 minutes, then fluff with a fork and allow to cool.
In a small bowl, whisk together olive oil, lime juice, ground cumin, minced garlic, salt, and black pepper until well combined. In a large bowl, combine the cooled quinoa, black beans, red and green bell peppers, corn, red onion, and cilantro. Toss gently to mix.
Pour the vinaigrette over the salad and toss until everything is well coated. Adjust seasoning to taste.
Top with your favorite optional ingredients. For the best flavor, let the salad chill in the refrigerator for at least 30 minutes before serving.