Rinse quinoa in a strainer, put into a small saucepan with the water, and bring to a boil. Reduce the heat and simmer, covered, for 15 minutes. Fluff with a fork and let cool with lid off.
1 cup quinoa, 1 ½ cup water
In the meantime, mix the dressing ingredients together in a small bowl or measuring cup.
¼ cup lemon juice, 2 tbsp olive oil, ¼ tsp cumin, ½ tsp salt, 1 pinch pepper
In a large bowl, toss together the black beans, green onion, celery, tomato, cucumber, cilantro or parsley and most of the cheese, leaving some for sprinkling on the top.
19 oz black beans, 4 stalks green onion, 2 cups celery, 1 large tomato, ¼ cup cucumber, ½ cup cilantro, 6 oz feta cheese
Add the cooked quinoa and dressing, and toss gently.