Place the potatoes in a medium saucepan and cover with cold water, add a good pinch salt. Cover and bring to the boil over high heat. Remove the lid and cook, for 25-30 minutes or until just tender.
Meanwhile, pick leaves from the coriander and place in a bowl of iced water and refrigerate until later. Cut roots from coriander stems and rinse well then place roots into a small food processor with the ginger, garlic, chilli, lemon rind and process until finely chopped. Add lemon juice, fish sauce and palm sugar, process until well combined. Transfer to a large bowl. Stir in oil, taste and adjust the sugar and fish sauce as needed.
Drain the potatoes and set aside for 10 minutes or until cool enough to handle, then cut into pieces about 3cm and while warm add to the dressing, toss gently to coat. Set aside to cool to room temperature.
Just before serving add the drained coriander leaves, mint, basil and peanuts. Toss gently to combine then serve.