For Sichuan poached chicken, place ingredients and 1 tsp sea salt in a saucepan and cover well with cold water. Bring to the boil, then remove from heat and stand for 5 minutes or until chicken is cooked through. Drain and shred chicken, and refrigerate to chill (10-15 minutes).
For Sichuan spiced oil, heat oil and star anise in a saucepan over medium-high heat until oil shimmers (1-2 minutes). Combine remaining ingredients in a heatproof bowl, strain oil over (discard star anise), mix to combine and set aside. Sichuan oil will keep for a week in a sealed jar.
Cook noodles in a saucepan of boiling water over medium-high heat until tender (2-3 minutes), then drain and rinse under cold running water. Transfer to a bowl, shaking off excess water. Add grapeseed oil, soy sauce, vinegar, sugar and garlic, toss to combine, then add cucumber, spring onions and shredded chicken, drizzle over Sichuan oil to taste, toss to combine and serve scattered with sesame seeds and extra spring onion.