In a small saucepan, combine quinoa, stock and salt together. Bring to the boil; reduce heat to gentle simmer, cover with a lid and cook for 15 minutes or until broth has absorbed and quinoa is soft. Remove from heat and set aside while still covered and allow to steam. After about 2 minutes, fluff with a fork. Allow to cool slightly and add the lemon juice.
Add the chicken fillets in a large skillet or nonstick pan with the olive oil, balsamic vinegar, lemon juice, stock powder and garlic powder/granules. Saute the chicken until nice, crispy and golden on both sides, and cooked through. Remove from heat; allow to cool slightly, and slice into 1-inch strips.
Combine all dressing ingredients in a small bowl/jug, and whisk until mixed through.
Combine the lettuce, tomatoes, onion, olives, Feta and parsley together in a large salad bowl. Top with chicken slices and quinoa, and drizzle with the dressing. Toss to combine. Serve with lemon wedges.