Warm the rice vinegar, sugar and salt in a small saucepan until everything has dissolved, then set aside to cool.
Blanche the samphire for 1 minute in a small pan of boiling water, then transfer to a bowl of iced water for a few minutes to prevent it from cooking further.
Drain, pat dry with kitchen paper and add to a bowl with the sliced radishes, carrots and chilli. Pour the pickling liquid over the vegetables, squeeze over the lime juice and leave to sit at room temperature for 30 minutes.
Heat 1/2 tbsp oil in a small frying pan. Cook the shallots, garlic chilli and ginger for 6-8 minutes. Set aside and leave to cool.
In a food processor, add the chicken thighs, coriander leaves, cooked shallots, chilli and ginger, plus a pinch of salt and pepper. Blitz to a course mince, then whizz in the egg. Divide the mixture into 8 portions.
Heat the oven to 200°C/180°C fan)/gas mark 6. Bash the fat ends of the lemongrass sticks with a rolling pin, then shape an oval portion of meat around each flattened end (make sure that each stick sits in the centre of the chicken). Fry the skewers for 5 minutes on a hot griddle pan, then transfer to the oven to finish cooking for 20 minutes.
Drain the pickled vegetables and serve with coriander leaves and lime wedges.