In a small saucepan, combine the quinoa and water and bring to a boil. Once boiling, reduce heat, cover, and simmer. Simmer over low heat for 15-20 minutes. Once the water is absorbed, turn off the heat.
While the quinoa cooks, make the dressing. In a small bowl, combine the oil, lime juice, honey, salt and cayenne pepper. Whisk the ingredients until thoroughly combined.
In a separate large mixing bowl, combine the cooked quinoa, radish, black beans and scallions. Pour the dressing over the quinoa mixture and refrigerate. Serve cold.