Heat a little oil in a pan and add cumin seeds ginger paste, chopped green chillies, a few curry leaves and chopped onion. Saute till the colour of onion turns golden. Add turmeric powder, red chilli powder and black pepper powder to the masala. Add minced fish to it and mix well. Mix the fish with mashed boiled potatoes and chopped leek. Once mixed well keep the mixture aside for cooling. Later transfer it to a bowl and mix it again with the hand. Add a little lemon juice and mix again. Make small cutlet shapes out of the mixture. Beat eggs in a separate bowl and in another bowl, take some bread crumbs. Dip the fish cutlets in the beaten egg first and then coat them with the bread crumbs. Heat oil in a pan. Shallow fry these cutlets. Fry till the colour turns a golden brown. Once both sides are fried, drain the excess oil using an absorbent paper. Transfer them to a serving plate. Serve the cutlets with any chutney you wish to have.