Gently wash produce under cool running water, pat dry, and prepare as directed.
Cook the quinoa with the cumin in the broth for 12-15 minutes, until the liquid is absorbed.
Cool slightly, then transfer to a large bowl and add the beans, tomato, and corn.
Whisk together the lemon juice, olive oil, cilantro, scallions, and garlic to make a dressing, and stir into the salad.
Chill 2-4 hours before serving.