Heat 4 cups of water over high heat until boiling. Stir in quinoa and reduce the heat to low.
Simmer, on low, for 8-10 minutes. Remove from heat, cover and let stand for 10 minutes.
Heat oil in pan over medium heat. Add onion and garlic and sauté for 5-7 minutes. Add to quinoa. Stir in cranberries and walnuts.
In a small bowl, combine the apple cider vinegar and parsley. Stir well. Pour over quinoa and stir to combine. Serve immediately.