Set the oven at 160C fan/gas mark 4.
Put the chicken in a roasting tin, brush with a little olive oil and season with salt and black pepper. Bake for 30-35 minutes till the skin is crisp and golden and the juices are clear when the flesh is pierced with a skewer. Set aside, reserving the roasting juices.
Peel the ginger. Peel the cucumber, slice in half lengthways then scrape out the seeds and pulp from the centre with a teaspoon. Cut the flesh into pencil thin slices and put them in a mixing bowl.
Remove the chicken from the oven when it is ready, leave to rest for 10-15 minutes, then slice each breast into three thick pieces and add to the cucumber.
Cut the limes in half and squeeze them into a bowl. Peel the mangoes and thickly slice the flesh, keeping the cut pieces brushed or dipped in a little of the lime juice to stop them browning. Finely grate the ginger into the lime juice, then stir in the fish sauce and palm sugar.
Pull the parsley leaves from their stems and add to the dressing, together with the reserved roasting juices. Toss the mango and chicken with the dressing.
Pile on to a large dish or into a bowl and serve while the chicken is still warm.
