1Firstly, put the sweet potato on a lined baking tray, drizzle with 1 teaspoon of the sesame oil and place into a 180 degree celsius preheated oven to roast for about 20 minutes. When ready, remove from the oven and set aside to cool.
2Meanwhile, place the miso, spring onion, chicken and 2 cups (500ml) water in a medium saucepan over high heat, bring to a simmer and reduce heat to low. Cover with a lid and gently poach for 10-12 minutes until chicken is cooked. Remove from heat, and allow to sit in poaching liquid for 20 minutes before removing from pan. Reserve 1/2 cup (125ml) strained liquid for the noodles. Thickly slice or shred the chicken.
3Cook the noodles in a medium saucepan of boiling salted water for 3-4 minutes. Drain the noodles under cold running water and transfer to a bowl. Pour over reserved strained poaching liquid and remaining teaspoon of sesame oil, and mix to combine. Cover and refrigerate until required.
4For the dressing, place all ingredients in a food processor and blitz until smooth.
5To serve, gently toss noodles with chicken, sweet potato, cucumber and dressing. Place onto a serving platter, top with extra spring onion, sesame seeds and drizzle with any remaining dressing and a generous squeeze of fresh lime juice.