Use a 6-quart slow cooker, with a wire rack inside. I used the little rack that came with my rice cooker. Skin the duck, and remove the neck and giblets (ick).
Mix the oregano, pepper, garlic salt, and lemon zest and cornstarch in a small bowl. Rub the mixture all over the duck, inside and out. Place the duck onto rack, breast side up.
Use the same bowl (might as well) to mix the wet ingredients together. Pour over the top of the duck. Cover and cook on high for 4 hours, or until a meat thermometer registers 165° to 180°F.
Duck. It’s what’s for dinner! I don’t eat much duck, but I liked this tremendously. The glaze is quite tasty, and I recommend making a bit more to have for dipping. My kids really liked the sauce a lot, and dipped their “chicken” into it. I told them they were eating duck, but they didn’t believe me.