In a small bowl, combine the sugar, salt and water and stir until dissolved. Set aside.
Heat 2 teaspoons of the vegetable oil in the wok over medium-low heat. Add the onion and rice vinegar and sauté for 10 to 15 minutes or until caramelized. Remove the onion from the wok.
Heat the remaining 2 teaspoons of vegetable oil and the sesame oil in the wok over medium heat. Toss in the corn, carrots, peas, and stir-fry for about 6 minutes, or until the corn and carrots are tender. Mix in the sugar mixture, pine nuts, and onion and stir-fry for one minute longer. Serve hot.