Combine the wheat flour, baking powder, and 5 g of salt in the large mixing bowl.

Pour in the 500 ml warm water and 100 ml vegetable oil, then mix until a shaggy dough forms.

Knead the dough for 8 minutes until smooth and elastic.

Cover the dough and let it rest for 30 minutes at room temperature.

Finely chop the onion, garlic, and fresh ginger for the filling.

Heat 15 ml vegetable oil in the deep frying pan and sauté the chopped onion until softened.

Add the garlic and fresh ginger, then cook for 1 minute until fragrant.

Stir in the drained canned tuna and break it into small flakes with the wooden spoon.

Season the filling with black pepper, paprika, ground cumin, sweet chili powder, and 3 g salt.

Cook the tuna filling for 3 minutes, then transfer it to a small bowl to cool completely.

Finely chop the 450 g onion for the sauce.

Heat 30 ml vegetable oil in the saucepan and sauté the sauce onion until golden.

Add the tomato paste and cook it for 2 minutes, stirring continuously.

Add 200 ml water and stir until the tomato paste is fully dissolved.

Season the sauce with chili powder, black pepper, 2 g salt, and sugar.

Simmer the sauce for 15 minutes until thickened, then keep warm over low heat.

Divide the rested dough into 60 equal balls.

Roll each dough ball into a thin 10 cm circle.

Place about 1 teaspoon of cooled tuna filling in the center of each dough circle.

Fold each circle into a half-moon and press the edges firmly to seal.

Heat the remaining vegetable oil in the deep frying pan to 175°C / 350°F.

Fry the sealed pastels in batches for 3 to 4 minutes until deep golden and crisp.

Drain the fried pastels on paper towels and serve them hot with the tomato onion sauce.