Step 1Prepare the duck: In a large pot of boiling water, blanch duck for 30 seconds. Transfer to a large bowl and use a heatproof measuring cup to carefully pour boiling water into the bird for a thorough blanching. Drain completely and pat dry with paper towels.

Step 2Combine salt and sugar and rub mixture all over and inside the duck. Let stand on a cooling rack for 1 hour at room temperature, then pat dry again.

Step 3Meanwhile, make spice rub: In a medium bowl, whisk together all remaining duck ingredients. Rub mixture all over and inside the duck. Transfer to a cooling rack set over a baking dish and refrigerate for 2 days.

Step 4Make the stuffing: Preheat oven to 350°. In a large bowl, toss together cauliflower, onion, garlic, salt, pepper, and oil until evenly combined then transfer to a large baking sheet. Bake for 25 minutes, then add hoisin and Sriracha, tossing to coat evenly. Return to oven to continue baking, tossing every 12 minutes, until greens are golden and half-crispy, about 25 minutes more.

Step 5Stuff duck with roasted greens mixture, then pin wings into the body with toothpicks, and secure legs with twine and tuck under the fat flap to prevent burning.

Step 6Bake duck breast-side up for 35 minutes. Flip the bird and bake for 35 minutes more. Flip once more and bake until internal temperature reaches at least 155°, 15 to 20 minutes more. Increase oven temperature to 400° and continue roasting until deeply golden and perfectly bronzy, about 15 minutes more.

Step 7Meanwhile, make orange glaze: In a small pot over medium-low heat, combine all ingredients and bring to a simmer. Reduce for 20 minutes, or until mixture thickens to a slightly syrupy consistency.

Step 8Let duck rest for at least 20 minutes before carving. Serve with orange glaze, cucumbers, and green onions.