Heat the oil in a saucepan on medium-high heat. Oil should be moderately hot add cumin seeds. After the cumin seeds crack, add the spinach.
Stir-fry, making sure to press the spinach down so the water can evaporate. Cook the spinach until most of the water has evaporated. Spinach still should be moist not dry.
After spinach is at room temperature, add to the potatoes with all other ingredients, ginger, cilantro, green chilies, salt, and corn starch. Mix will be the consistency of soft dough.
Divided the mix to 20 equal parts and roll them into oval shapes.
Heat the oil in a frying pan on medium heat. The frying pan should have about 1 inch of oil. To check if the oil is ready, put small piece of the mix in oil. It should sizzle and come up slowly. If oil is very hot kababs will not cook through and will not be crispy.
Fry the kababs in small batches. Fry kababs until golden-brown all around, this should take about 6-7 minutes.
Serve them hot with sweet and sour tamarind chutney.