Put sifted flours into a mixing bowl. Add in salt and butter to mix until mixture resembles coarse crumbs. Stir in water and lime juice, a tablespoon at a time. Mix until a soft dough is formed.
Mix the dough into a big round ball. Wrap with cling film or cover with a piece of damp tea-towel and rest for 30 minutes.
Roll pastry margarine between two sheets of plastic into a rectangle (25x18cm).
Remove dough onto a lightly floured table top, roll out the dough into a rectangle (52x38cm). Put the pastry margarine in the centre of the dough. Fold both the sides of the dough to cover the pastry margarine, ensuring that the pastry margarine is completely enclosed.
Roll out the dough into 51x30cm rectangle and fold into three. Repeat rolling, folding and chilling procedure. Roll out dough into a big rectangle on a lightly floured surface. Using a sharp knife, cut into squares. Place a tablespoon of sardine filling in the centre. Fold into a triangle. Seal the edges with a little water. Use a fork to press down the edges to seal. Bake in preheated oven at 200°C for 1520 minutes.
To prepare the filling: Heat oil in a wok and sauté ginger and onion until fragrant. Add in chilli paste to mix. Stir in sardines and fry until fragrant. Add tomato sauce seasoning and fry until well combined. Keep stirring over low heat until the sauce is thick. Dish out to cool completely.