Preheat the oven to 180°C, fan 160°C, gas 4. In a food processor, whizz the prawns, pollock, cornflour, lime zest, coriander, chilli, soy sauce and sesame oil until fully combined. Roll into 12 balls and then flatten slightly into patties.
Heat the olive oil in a large frying pan and fry the fish cakes for 2-3 minutes on each side. You may need to do this in batches. Transfer to a baking tray and cook in the oven for 15-20 minutes.
Meanwhile, prepare the salad and dressing. Whisk the rice wine vinegar with the fish sauce, sugar and lime juice. Drizzle over the cucumber and radish salad and serve the salad with the fish cakes. Also great served with sweet chilli sauce for dipping.