Put the potatoes into a large pan of lightly salted cold water and bring to the boil. Cook for 6 minutes or until tender to the point of a knife. Drain well and cool completely.
Heat 2 tsp of vegetable oil in a non-stick frying pan and cook the potatoes,turning, until they are golden and crisp. Tip out onto a plate.
Add another tsp of oil to the pan and fry the cumin and mustard seeds for 1 minute.Tip in the leeks and cook gently for 20 minutes until they’re very soft, adding a splash of water if they catch. Add the potatoes to the pan and stir to combine, then sprinkle in the curry powder, stir again and cook for 1 minute.Keep warm.
Ina separate lidded frying pan, heat 1 tsp of oil over a high heat. Crack in the eggs and fry for 1 minute until starting to crisp, then put on the lid and cook until the whites are cooked through but yolks still runny.
Stir the lime juice and cilantro through the tomatoes. Plate up the hash and serve with the fried eggs on top, then spoon over the tomato salsa.