Heat oil in a saucepan over medium heat. Add onion, celery and carrots and cook and stir for 10 minutes or until vegetables are tender.
Using a sieve, rinse quinoa under cold water. Drain well. Add to the vegetables and cook and stir for 1 minute. Add water, bay leaf and lemon zest and juice, bring to the boil. Cover, and reduce heat to medium low. Simmer for 15 to 20 minutes, or until liquid is absorbed and quinoa is tender.
Discard bay leaf. Stir in peas, and season to taste with salt and pepper. Serve.