Boil potatoes in plenty of water until tender, about 20 minutes.
Peel the potatoes and place them in refrigerator until cold.
Cut them into small cubes or 1/2" thick slices and keep aside.
In a small bowl, put together imli ka ras, sugar, salt, chili powder, khatai powder, chaat masala, and stir to mix the ingredients.
In a large bowl, combine potatoes, tomatoes, onions, green chilies, and coriander leaves.
Pour imli mixture over potatoes mixture and stir gently with a wooden spoon to coat the potato with spices. Taste for right amount of salt and sugar.
Serve warm or cold. To serve warm, microwave for 1 minute.