Step 1In a small bowl, combine the chives, shallots, lemon zest and parsley and set aside.
Step 2Cut the albacore into 10 pieces about 2 inches by 1 1/2 inches (each piece will be about 3 ounces). Season each piece with one-fourth teaspoon salt and a pinch of pepper.
Step 3In a medium bowl, whisk together the eggs with 2 tablespoons of the herb mixture (reserve the remaining amount) and set aside. Place the panko in another medium bowl.
Step 4Dredge the fish in the egg mixture, then in the panko; place on a parchment-lined baking pan. Refrigerate, uncovered, for 30 minutes.
Step 5Fill a medium, heavy pot with enough oil to come about 3 inches up the sides (or use a deep fryer). Heat the oil until a thermometer inserted reads 375 degrees. Fry the fish, a few pieces at a time, until the panko turns golden and the fish is seared, a little over 1 minute. Set the fish aside on a paper towel until all of the fish is fried. Slice each piece lengthwise into four slices.
Step 6To assemble a baco, place a flatbread on a plate. Spoon about 1 tablespoon ancho-pomegranate sauce over the bread, top with two slices of avocado, then four slices of the fish. Top the fish with a scant tablespoon each of pickled onion and salbitxada and a teaspoon of garlic-chive cream (or to taste). Drizzle a good pinch of the reserved herb mixture over the top. Gently fold one end of the flatbread over to form a sandwich, and serve immediately. Repeat with the remaining flatbreads.