Cook the quinoa according to package directions and drain on 2 layers of paper towels. Transfer to a mixing bowl. Add the cauliflower, grapes, scallions, and avocado pieces.

In a small bowl, whisk together the vinegar, lime juice, honey, cumin, oregano, and salt until blended. Gradually whisk in the oil. Drizzle the dressing over the quinoa mixture and toss gently. Season to taste with pepper.