Combine the lime zest, ginger, chopped garlic, 1 tsp of the cumin, chilli powder, half the coriander and 1/2tbsp of the olive oil in a bowl. Add the prawns and then toss to coat. Leave to one side to marinate.
Mix the tomatoes, 1/4 of the onion, lime juice and another 1/2 tbsp of the oil in another bowl and set to one side.
Coarsely grate the potatoes, squeezing out the excess liquid. In a large bowl, season the potato and then shape into rostis. Fry the rostis in a large pan until golden and crisp.
Heat a small pan, fry the remaining onion in the rest of the oil, adding the crushed garlic, remaining cumin and chipotle paste and stir well!
Tip in the beans with a splash of water, stir and cook gently until heated through. Stir in the tomato mixture and cook for a further minute, season well and add the corriander.
Whilst the beans are heating, fry the eggs and heat the griddle pan over a high heat and grill the prawns for 1 minute on each side or until pink and cooked through.
Plate the bean mixture on top of the rostis and top with avocado slices, grilled prawns and fried eggs.