Bring duck to room temperature. Rinse duck and pat dry. Remove neck and giblets and save for another purpose. Pierce the duck skin all over with tip of sharp paring knife, without penetrating the meat.
Mix together salt and 5-spice powder. Season interior of duck with half of the salt mixture; use remainder to season exterior.
Combine orange zest with grated ginger and garlic, then season inside cavity with mixture. Place orange wedges in cavity and tie legs together. Secure neck flap with wooden skewer or toothpicks. Place duck on rack in roasting pan breast-side-up.
In a small saucepan bring orange juice, honey, maple syrup, and liquid aminos to a simmer. Add sliced ginger and star anise. Reduce mixture until glaze thickens, about 10 minutes. Remove from heat and set aside.
Roast duck for 2 hours, carefully pouring off fat and turning duck over every 30 minutes. Baste with glaze every time you turn the duck over, 2.5 hours in all. (Tent with foil if glaze begins to get too dark.) Duck is done when temperature at thickest part of leg reads 165 degrees.
Let rest 20 minutes. Serve garnished with sage leaves and roasted oranges if desired.