Bring a large saucepan of lightly salted water to a boil. Add pasta and cook for 8 to 10 minutes or until al dente; drain.
Meanwhile; heat oil in a small frypan over medium-low heat. Stir in sesame seeds and cook until golden brown. Remove from heat. Stir in soy sauce, vinegar and sugar. Pour dressing into a sealable container and set aside.
In a large bowl mix together pasta, cooked chicken and 1 cup dressing (reserve remaining dressing). Cover salad and refrigerate at least 6 hours.
Directly before serving stir in parsley, spring onions and spinach. Toss with remaining dressing, if desired.