Cut the tofu into roughly 2 cm cubes. Heat the oil in a non-stick pan and fry until golden on all sides. Add the soy sauce and rice vinegar as it cooks to help with colour and flavour. Once golden, add the sesame oil and seeds, toss to coat, and set aside.
Finely chop the garlic, ginger and spring onions.
Chop the carrot, pepper and green beans.
Heat the oil in a wok or large pan. Stir-fry the garlic, ginger, and spring onions for a minute until fragrant.
Add the carrot, green beans and pepper, followed by the soy sauce and rice vinegar. Stir-fry briefly, then add a splash of water and cook for a couple of minutes until the vegetables start to soften.
Take a spoonful of the cooking liquid and mix it with the miso paste in a small bowl until smooth.
Add the prawns to the wok and stir-fry until heated through (or until they turn pink if using raw prawns).
Return the tofu to the pan, add the miso mixture and lime juice, and toss everything together until well coated and heated through.
Serve hot with rice or noodles, and finish with a sprinkle of sesame seeds.