Bring a large pot of lightly salted water to a boil. Add spaghetti and cook according to package directions. Drain in a colander.
While pasta cooks, mix Salsa ingredients in a medium bowl until bended. Let stand at room temperature for flavors to develop.
Meanwhile, heat 1 tsp of the oil in a 10-inch ovenproof nonstick skillet. Add onion and saute until golden and tender, about 8 minutes. Scrape into a large bowl, add eggs and beat with a fork or whisk until blended. Stir in spaghetti, cilantro and salt and pepper.
Heat broiler. Wipe skillet clean, add remaining 2 tsp oil and heat. Pour in egg mixture, cover and cook over medium-low heat 8 minutes or until bottom is light golden and only the top remains uncooked. Place under broiler 1 1/2-2 1/2 minutes or until top is set.
Loosen edges with a rubber spatula. Slide "pie" onto a serving plate, cut in wedges and serve with the salsa.