Thai minced chicken salad

INGREDIENTS

• 2 lemongrass
• 4 lime leaves , stalks removed
• 2 red chillies , deseeded
• 3 garlic cloves
• fingertip-length piece fresh root ginger
• 4 skinless chicken breasts
• 1 tbsp vegetable oil
• 1 tbsp sesame oil
• 1 tsp chilli powder
• 50ml fish sauce
• 1 red onion , chopped
• 3 tbsp lime juice
• handful each mint , basil and coriander leaves, roughly chopped
• 3 Baby Gem lettuces , leaves separated
• 1 cucumber , seeds removed and cut into strips lengthways
• 200g beansprouts
• lime wedges, to serve