Cook quinoa with broth according to package directions.
While quinoa is cooking, combine beans, corn, avocado, tomatoes and onion and top with Cilantro dressing (the recipe is below) and toss gently. Taste, as it may not need any more salt (mine did not). Add salt and pepper if desired and the lime zest to taste (I added the full 1/2 lime zest). Add 1/2 of the chopped cilantro if desired, and gently toss once more and set aside.
When quinoa is cooked, drizzle with olive oil. If you are watching calories and fat go light on the oil here or omit as the bean mixture has plenty! Toss and add salt and pepper to taste.
When ready to serve, spread the quinoa on a large platter and top with bean mixture. Garnish with chopped cilantro if desired.
Cilantro Dressing: Place last 6 ingredients in a container with tight fitting lid and shake! Taste and adjust.