Sesame spring onion stir fried udon with crispy tofu

Name: Sesame & spring onion stir-fried udon with crispy tofu
Ingredients: 400g block firm tofu; 1 tbsp cornflour; ½ -1 tsp chilli flakes, to taste; ¼-½ tsp Szechuan peppercorns, ground, to taste; 1 tbsp vegetable oil; bunch of spring onions, trimmed and cut into lengths; 200g green beans, trimmed and cut into lengths; 400g ready-to-use thick udon noodles; ½ tbsp sesame oil; 2 tsp sesame seeds, plus a pinch to serve; 1 tbsp low-salt soy sauce, plus extra to serve; 1 tbsp rice vinegar