Remove the tough outer leaves from the lemon grass and finely shred the core. Heat the oil in a large frying pan or wok, add the garlic and lemon grass and cook for 30 seconds. Stir in the ginger and pork and cook for 5–7 minutes until the pork is just cooked through. Stir the sugar into the fish sauce to dissolve, add the lime rind and stir into the pork. Cook for a further 1 minute until glossy and coated.
Make the salsa by tossing together all the ingredients and seasoning to taste. Prepare the rice noodles if necessary according to the pack instructions. Mix together the pork, separated lettuce leaves and noodles and divide between 4 serving plates. Scatter over the fresh coriander and top with the mango salsa.