In a small bowl, whisk together the olive oil, vinegar, Dijon mustard, lemon juice, and salt. Season to taste with more salt if necessary, and freshly ground black pepper.
In a medium bowl, stir together the quinoa, dried cranberries and golden raisins, sunflower seeds, shredded carrots and salad dressing. Gently stir in the avocado and feta cheese. Spoon into the lettuce cups and serve.