Heat the oil in a frying pan on medium-high heat. Oil is the right temperature when cumin seeds crack immediately after being put in the pan.
Add cumin seeds after seeds crack add potatoes and sprinkle the salt over potatoes.
Stir-fry until potatoes are light golden brown this should take about 6-7 minutes. Add ginger, green chilies and chili flakes. Stir for about a minute.
Add tamarind paste, and sugar mix it well. Add water as needed about 2-3 tablespoons. Potatoes should be moist.
Turn off the heat and add cilantro. Mix it well and serve chatpata aloo hot.