How to Make It
Bring a large pot of salted water to a boil and prepare an ice bath. Blanch the zucchini until tender-crisp, about 3 minutes, remove and shock in an ice bath for 1 minute until cool. Drain and puree the zucchini with garlic, yogurt, tarragon, cilantro, and chives in a blender until smooth. Season with salt and pepper to taste.
Heat the oil to 350° in a very large enameled cast iron pot. Fry the sliced potatoes in 3 batches, separating the slices as you add them to the pot. Keep the oil between 340° and 350°. Be careful as the oil may splatter. Stir with a slotted spoon so the chips stay separate. Remove when they turn golden brown, about 4 minutes, and place on a plate lined with a paper towel. Season with salt immediately.
Combine the flour and lemon juice and zest. Add the cold sparkling water, black pepper, and sesame seeds and mix thoroughly. One filet at a time, dip fish in batter, coating each piece completely, and let extra batter drip off fish.
Fry battered fish for approximately 3 minutes or until golden brown. Remove and place on a plate lined with a paper towel. Season with salt immediately.
Serve the fried fish and potatoes with the dipping sauce.