In a mixing bowl, combine the flour and salt. Gradually add water and knead until you get a smooth and elastic dough. Cover the dough with a damp cloth and let it rest for about 30 minutes.
In a large bowl, combine the mashed potatoes, chopped spinach, green onions, cilantro, minced garlic, ground cumin, ground coriander, red chili flakes, salt, and pepper. Mix well until all ingredients are thoroughly combined.
Divide the dough into small balls, about the size of a golf ball. Roll each ball into a thin circle on a lightly floured surface.
Place a generous spoonful of the filling mixture onto one half of each dough circle. Fold the other half over the filling to form a half-moon shape. Press the edges to seal well, using a little water if necessary to help the dough stick.
Heat a thin layer of oil in a large skillet over medium heat. Fry the bolani in batches, cooking each side for about 2-3 minutes or until golden brown and crispy. Add more oil as needed.
Remove the bolani from the skillet and drain on paper towels to remove excess oil. Serve hot with yogurt or chutney.
Enjoy your meal!