Preheat oven to 450°F. Prepare Cilantro Chile Sauce. Set aside.
Whisk eggs and ¼ teaspoon salt in a medium bowl. Set aside. Heat olive oil in an 8½-inch ovenproof nonstick skillet over medium-high heat. Add onion. Cook and stir until onion is tender. Add potatoes and zucchini. Cover and cook for 3 minutes more or until potatoes are tender. Transfer vegetable mixture to a platter. Cover and keep warm.
Turn heat to medium lowt. Add egg mixture to same skillet. Cook for 5 minutes or until the eggs are just et. Run a spatula underneath the sides of the frittata and tilt the pan so the uncooked eggs run to the underside to cook. Drizzle the cooked eggs with some of the Cilantro Chile Sauce. Sprinkle potato and onion mixture over top.
Place skillet in the oven and bake for 9 minutes or until eggs are well set and puffy. Sprinkle blue cheese and, if desired, sunflower seeds on top during the last 2 minutes of baking. Remove from oven (be careful; the handle could be hot). Cut frittata into wedges and serve with extra Cilantro Chile Sauce.
Cilantro Chile Sauce: Place ½ cup olive oil; 2 tablespoons lemon juice; 2 small bunches fresh cilantro; 2 large cloves garlic, peeled; 1 green chile pepper, seeded and cut up; ¼ teaspoon ground cumin and ½ teaspoon sea salt in a food processor. Cover and process until smooth.