Remove skin from duck breasts. Place duck breast, stock, soy and star anise in a medium saucepan; bring to the boil. Reduce heat; simmer, uncovered, 3 minutes. Remove from heat. Cool duck in poaching liquid.

Meanwhile, heat oil in a small frying pan; cook duck skin until crisp. Remove with a slotted spoon; drain on absorbent paper. Drain fat from pan.

Heat cleaned frying pan over medium heat; cook sugar and nuts, stirring, about 5 minutes or until caramelised. Pour onto a baking-paper-lined tray; cool.

Make lime dressing. Combine garlic, sugar, fish sauce, lime juice and peanut oil in a small bowl until sugar dissolves.

Place noodles in a large heatproof bowl, cover with boiling water; stand until just tender. Drain; return noodles to bowl.

Halve cucumber lengthways; remove seeds. Cut cucumber into matchsticks. Add cucumber to noodles with carrot, shallots, chilli, sprouts and ½ cup of the dressing; toss gently to combine.

Thinly slice duck and duck skin. Coarsely chop nuts.

Add herbs to salad; toss gently to combine.

Serve salad topped with duck; sprinkle with skin and nuts, drizzle with remaining dressing.