In a heavy 10 to 12-inch skillet, heat the oil over moderate heat until a light haze forms above it. Drop in the onions and, stirring frequently, cook for 8 to 10 minutes, or until they are soft and golden brown. Watch carefully for any sign of burning and regulate the heat accordingly. Add the tomatoes, 1 tablespoon of the chilies, the garlic and sugar, and cook briskly, uncovered, stirring from time to time, until most of the liquid in the pan has evaporated and the mixture is thick enough to hold its shape lightly in a spoon. Stir in the cod and potatoes, reduce the heat to low, and cover tightly. Simmer for 20 to 25 minutes, or until the fish flakes easily when prodded gently with a fork. Taste for seasoning. Serve the gesmoorde vis at once, mounded on a heated platter or in a large bowl. Sprinkle with the remaining teaspoon of chopped chilies and arrange the lemon wedges and parsley sprigs decoratively on top. Serve accompanied, if you like, by hot boiled rice and lemon or green bean atjar. Makes 4 to 6 servings. From "African Cooking", Laurens van der Post and the editors of Time Life Books, "Foods of the World" series, 1970. LOC # 77-119620.