Heat 2tbsp oil in a pan, add chopped onions and cook till they turn golden brown, about 5~6 minutes.
Next add green chilies and cook for a minute. Add the chopped ginger and tomatoes; cook till tomatoes turn mushy.
Add the cooked chickpeas along with ground coriander, cumin, red chili powder, amchur powder, chole masala and salt; cook for 5~6 minutes for the flavors to mingle.
Add the reserved cooking liquid and bring to a boil. Add more water if there is not enough cooking water.
Lower the heat and simmer for 10~12 minutes or till the gravy thickens little bit.
When the gravy thickens, add some julienned ginger to the chickpeas.
Serve hot wit the garnishes of choice.