Chill the fingers. Take them out of the refrigerator, drizzle 1 tbsp oil, ½ tsp red chilli powder and salt over them and mix well.
Put them in the air fryer basket, fit the basket into the main body and cook at 200°C till they turn golden and crisp. Heat the remaining oil in a non stick pan, add spring onions and garlic and saute.
Add ginger and saute till lightly coloured. Add 2 tbsps tomato ketchup and mix. Add soy sauce and chilli sauce and mix. Add ½ cup water and mix and let it come to a boil.
Reduce heat and simmer. Add half the cornstarch mixture and mix and cook till the sauce thickens. Add crushed red chillies and mix. Switch off heat. Transfer the sauce into a bowl.
Place the potato fingers in a serving bowl, pour the chilli sauce over, garnish with spring onion greens and serve immediately.