Combine the cherry tomatoes, avocado and lime juice in a small bowl with some seasoning. Set aside.
In a food processor, whizz together the kidney beans, sweetcorn, lentils, sweet chilli sauce, red onion, white bread, flour and seasoning until well combined. Form four equal burgers.
Heat the olive oil over a medium-low heat in a large non-stick frying pan. Fry the burgers for 3-5 minutes on each side until nicely browned.
Place each burger on the bottom half of each roll. Top with the tomato and avocado salsa and sandwich together with the top half of the roll.