In a wide bowl, sift together maida and besan flour. Add onion julienne, finely chopped green chilies, and coriander leaves.
Mix the onions to the flour along with soda, fennel seeds, salt, and red chili powder. Sprinkle just enough water for everything to form a dry batter.
Heat cooking oil and fry small portions on all sides till golden brown.
Drain on a kitchen towel and serve hot.