In a blender, puree the orange, juice, soy sauce, ginger and sugar until smooth.
Transfer to a large bowl, add the chicken and turn to coat.
Cover and refrigerate for at least 1 hour or up to 24 hours.
Heat the oven to 400°F.
Set a wire rack in rimmed baking sheet, then arrange the chicken, with marinade clinging, skin side up on the rack.
Bake until the thighs reach 170°F, about 45 minutes.
Turn the oven to broil and broil until the chicken is deep golden brown and lightly charred, 2 to 4 minutes.
Serve with orange wedges.