Place the quinoa, water, and beets into the inner pot and stir. Secure the lid, ensuring that the steam release handle is in the Sealing position. Press the Pressure Cook button and set the cooking time for 0 minutes. When the cooking time is complete, let sit for 10 minutes to naturally release the pressure. Turn the steam release handle to the Venting position to release any remaining pressure.
Press Cancel and remove the lid. Stir and then place the quinoa and beets into a large bowl and let cool for at least 10 minutes. Add the oil, celery, green onions, parsley, lemon juice, cumin, salt, pepper, and walnuts. Mix well. Serve at room temperature.