Between the sweetness of the mandarin oranges and the cayenne-spiced pecans, flavor explodes in each bite of this salad. Top it off with Chinese five spice mustard dressing to really make your taste buds happy.
Combine reserved liquid from mandarin oranges, canola oil, olive oil, mustard, cloves, and Chinese five-spice powder in a jar with a tight-fitting lid; seal jar and shake vigorously until the dressing emulsifies.
Melt butter in a saucepan over medium heat. Stir pecans and sugar into the butter; let simmer until hot, 1 to 2 minutes. Season the pecans with rosemary and cayenne pepper; continue cooking another 1 to 2 minutes. Remove from heat and drain pecans on a plate lined with paper towels.
Toss spinach leaves and green onion together in a large mixing bowl; top with mandarin oranges and pecans. Drizzle dressing over the salad to serve.