Start by scrubbing the sweet potato to remove any dirt. Cut it up into thick wedges, and place onto a greased baking sheet. Drizzle with 1 tbsp of olive oil and bake in the oven at 200`c for 20 minutes, or until the potato chips are cooked through. Alternatively you can deep fry the chips till golden brown. Cut the salmon into chunks and poach for a few minutes in boiling water till almost cooked. Drain away the water and leave the salmon to cool. Place the salmon, spring onions, ginger, chilli, beaten egg and seasoning together in a bowl and mix well to form a soft paste. Divide the mixture into small patties. Heat the remaining oil in a large pan and fry the salmon patties on both side for a few minutes till golden brown. Serve the salmon fishcakes with the sweet potato wedges and chilli dipping sauce on the side.