Heat olive oil in a large saucepan over medium heat. Cook and stir onion, carrots, raisins, and pumpkin pie spice until onion becomes golden, about 5 minutes. Stir in quinoa and cilantro and allow to toast for a few minutes.
Pour orange juice and water in and stir well, bringing to a boil. Reduce heat cook until all the liquid is absorbed, about 15 minutes.
Remove from heat and let stand for 5 minutes, then add walnuts. Fluff with a fork and serve.