In a large skillet over medium-high heat, heat 1 tablespoon of oil. Pour eggs into skillet. Add eggs set, lift edges, letting uncooked portion flow underneath. Remove eggs to a plate; set aside. In the same skillet, saute onion and celery in remaining oil until crisp-tender. Reduce heat. Add rice and ham; heat through. Stir in peas and corn; heat through. Meanwhile, chop egg into small pieces; gently fold into rice mixture. Sprinkle with soy sauce.