Prepare the Filling: While the dough is resting, prepare the filling. In a medium pan, heat 2-3 tablespoons of vegetable oil over medium heat. Add the chopped onion and sauté it for about 5 minutes, or until softened and fragrant.
Season the Filling: Add the cayenne pepper, oregano, curry powder, thyme, and salt to taste. Stir the seasoning into the onion, allowing the spices to toast slightly for about 1-2 minutes to release their flavors.
Add the Fish: Next, break up the fried mackerel and add it to the pan, along with the sardines (with their tomato sauce). Mix everything together, breaking up the fish into small, manageable pieces. Continue to cook the filling for about 5 minutes, stirring occasionally. The mixture should be fragrant and well-combined. Set aside to cool slightly.
Roll Out the Dough: After the dough has rested, place it on a floured rolling surface. Divide the dough into smaller portions, and roll each portion out into a thin sheet using a rolling pin. The dough should be about 1/8 inch thick.
Shape the Fish Rolls: Using a knife or pastry cutter, cut the rolled dough into rectangles. Place about 1 teaspoon of the fish filling in the center of each rectangle. Carefully fold the dough over the filling to form a roll, sealing the edges by pressing them together gently with your fingers or a fork. Repeat this process until all the dough is used up and all the rolls are filled.
