Bring a pan of water to the boil, add the sweetcorn, bring back to the boil, then drain. Set aside about a third of the sweetcorn in a bowl and put the remainder into a food processor. Add the cumin, curry paste and lime leaves and blitz, scraping
Add the spring onions, coriander, green beans and chilli to the sweetcorn bowl and mix, then add the sweetcorn paste into the bowl. Add the chickpea flour, baking powder, lime juice and 2 tablespoons of water. Season well and mix together into a thick batter that drops off a spoon, adding a dash more water if needed.
Pour about 1 1⁄2 tablespoons of oil into a wide frying pan over a medium-low heat. When shimmering hot, cook a nugget of the batter for a minute or two on each side. Taste to check the seasoning and heat level.
Divide the mix into four patties, each about 10cm across. Add two to the hot pan, then cook for 3–4 minutes, until deep golden on the bottom – turn the heat to low if they are browning any faster. Carefully flip them over and cook the other side until deep golden, about 3 minutes. Remove, keep warm and repeat to cook the remaining two burgers, adding more oil as needed.
Place the cucumber, carrot, chilli, shallot, lime juice and sugar into a small bowl and toss together.
Spread a little mayo or kewpie on the bottom of each bun, then add a quarter of the dressed veg and a pinch of the chopped nuts. Add a patty, then drizzle over a little sweet chilli sauce or Sriracha. Finish with coriander, lettuce leaves and the bun tops.