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 some seasoning until well combined. Form four equal burgers.
Heat the olive oil over medium-low heat in a large non-stick frying pan. Fry the burgers until nicely browned, about 3-5 minutes on each side.
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.