Wash and soak the chana dal for 2 hours. Remove stems, wash and grind the mint leaves into paste and set aside. Bring two cups of water to boil. Add salt, one table spoon of oil, mint paste, rice flour, soaked chana dal, red chilli powder and combine. Allow it to cool. Divide the dough into lime sized balls. Place the dough ball on a oiled plastic sheet and shape into a thin circle. Heat oil in deep frying pan. Deep fry the dough circles in hot oil till they turn crisp and light golden color. Remove from the oil and store in a air tight container.