Tear the stems out of the kale leaves then stack and slice into thin ribbons (chiffonade). A few cross chops will make the salad more manageable to eat.
Place the kale and onion in a large ceramic bowl and drizzle with lemon juice, olive oil, and agave nectar or honey. Sprinkle with salt and stir. Add cooked quinoa and avocado and gently combine. Cover and place in refrigerator to alllow the kale to relax with the lemon juice awhile, ideally 1–4 hours.