Prepare the dressing by combining all the ingredients except the oil in a bowl. Slowly pour in the oil while whisking.
Place the quinoa in a saucepan with the water and 1/4 teaspoon salt. Bring to a boil, reduce heat to a simmer, cover and let cook until the water is absorbed, about 15 minutes. Fluff with a fork.
In a salad bowl combine quinoa, remaining 1/4 teaspoon salt, orange, avocado, cumquats and beetroot. Toss to combine and drizzle with the dressing.