Mix the flour and water in a saucepan until smooth. Stir over a medium heat for 2–3 minutes or until thick, and set aside.
Finely chop 10 of the chives. Mix the prawns, water chestnuts, garlic, chopped chives, pepper and salt.
Clean and soak the remaining chives in hot water for 2 minutes until soft, then drain and dry.
Spoon 1 teaspoon of filling into the middle of a spring roll sheet. Use your finger to brush around it with flour paste, pull up the 4 corners and pinch together, enclosing the filling. Tie with a chive and lay on a tray. Repeat until finished.
Heat 7 cm (3 inches) of oil in a wok over a medium heat. The oil is ready when a small piece of spring roll sheet sizzles when dropped in. Deep-fry batches of 10 bags for 8–10 minutes until lightly browned and crispy. Drain on kitchen paper. Serve hot or warm, with Sweet Chilli Sauce (see