How to Make It
In a small bowl, mix 6 tablespoons of salt with the sugar. Spread half of the salt-sugar mixture on a large plate. Set the cod pieces on the plate and sprinkle the remaining salt mixture on top of them. Cover the cod pieces with another large plate and weight it down with a heavy can. Let the cod stand at room temperature for 30 minutes.
Meanwhile, in a medium saucepan of boiling water, cook the potatoes until tender, about 15 minutes. Drain, reserving 3/4 cup of the cooking water. Pass the potatoes through a ricer into a large bowl. Using the flat side of a chef's knife, mash the garlic with a generous pinch of salt until a paste forms. Using an electric mixer, beat the potatoes with the garlic paste, olive oil, yogurt and 2 tablespoons of the vinegar. Gradually beat in about 1/2 cup of the reserved potato cooking water at low speed until a smooth, loose sauce forms, using more of the cooking water if necessary. Add the oregano and season lightly with salt and pepper.
Rinse the salt cod and pat dry. Cut the cod into 1 1/2-inch pieces. In a large saucepan, heat 1 1/2 inches of vegetable oil to 350°. In a medium bowl, whisk the flour with the ale, eggs, anise seeds and the remaining 1 tablespoon of white wine vinegar until smooth. Add the cod chunks and turn to coat thoroughly with batter. Fry the cod in 3 batches over high heat until golden and puffed, 3 to 4 minutes. Using a slotted spoon, transfer the fritters as they are done to paper towels to drain. Serve hot, with the skordalia.