For the filling, toss all the ingredients together in a bowl until evenly combined, adding salt, pepper and lime juice to taste.
Lay a spring roll wrapper on a board with a corner facing you. Keep the rest covered with a tea towel to prevent them from drying out. Spoon 2 tbsp of the filling on to the bottom of the wrapper, then brush the surrounding pastry with egg white. Fold the bottom edge up over the filling, brush the sides with more egg white and fold them in and over the filling, like an envelope. Roll up into a log. Repeat with the rest of the wrappers and filling.
Heat the oil for deep-frying (at least a 6cm depth) in a suitable pan to 180°C To check the oil is hot enough, drop in a cube of bread - it should turn golden brown and crisp in 20 seconds. Deep-fry the rolls in batches for 40-50 seconds until golden brown and crisp. Drain on kitchen paper.
Cut the spring rolls in half on the diagonal and serve warm, with the ginger and coriander sauce on the side for dipping.
For the dipping sauce, dissolve the sugar and vinegar in a small pan over a low heat. Once completely dissolved, turn up the heat and boil for 5 minutes. Then add the chopped garlic, chillies, coriander and ginger.
Mix the remaining ingredients together then stir in the hot sugar syrup mixture. Allow to cool completely then pour into a screw-topped jar. Store in the fridge for up to 1 week. Bring the sauce to room temperature before serving.