Preheat the oven to 400ºF.
Rinse wings and drumettes and thoroughly pat them dry. Transfer to a large bowl and toss with vegetable oil and 1/4 teaspoon pepper until well coated. Position the wings on a baking rack in a single layer ensuring that the wings aren't touching.
Bake, rotating pan half-way through, until fully cooked, 45 to 50 minutes. Remove wings from oven and transfer to a large bowl.
In a medium saucepan set over medium heat, whisk together the soy sauce, water, pineapple juice, brown sugar, garlic and ginger. Cook, whisking constantly, until the sugar has dissolved fully.
In a small bowl, whisk together the cornstarch with 1 tablespoon water to make a slurry. Whisk the slurry into the sauce and simmer until it has thickened to the consistency of syrup, about 5 minutes.
Pour the sauce over the wings and toss them to combine. Serve immediately.