Mix flour, salt, and oil, then gradually add water to form a soft, pliable dough. Cover and let it rest for 30 minutes.
Heat a little oil in a pan, add hing, fennel seeds, and coarsely ground urad dal. Sauté until aromatic. Add coriander powder, red chili powder, and salt. Cook until the mixture is dry.
Divide the dough into small balls and the filling into equal portions.
Flatten a dough ball, place the filling in the center, and seal it by pinching the edges together.
Gently roll the stuffed ball into a flat disc, being careful not to tear it.
Heat oil in a deep pan on medium heat. Fry the kachoris until golden brown, flipping occasionally.
Drain excess oil and serve your crispy hing kachoris with tamarind chutney or spicy potato curry.