Place a folding metal steamer basket in the bottom of a large saucepot and add enough water to come up almost to the bottom of the steamer.
Arrange wings on steamer like spokes on a wheel with the large meaty end pointing out and the bony narrow bit pointing inward. If you're working with a standard steamer basket, you'll probably have to work in two batches.
Cover the pot and bring to a boil over high heat. When steam comes out from under the lid, reduce heat to medium and steam wings for 10 minutes.
Remove wings from basket with your trusty spring-loaded tongs and lay out on a wire rack set in a half-sheet pan lined with paper towels. Refrigerate 1 hour. If working in batches, make sure chill time is 1 hour from last batch.
Meanwhile, combine chili sauce, vinegar, and Dr. Pepper in a small saucepan and reduce down to a glaze, 20 to 30 minutes, over medium heat. Final volume will be about 1/3 original amount.
Crank oven to 425ºF and place rack in middle.
Remove paper towels from half-sheet pan and move wings to oven. After 20 minutes, remove wings to a large mixing bowl and toss with the glaze. Return to rack and roast another 10 minutes.
Arrange on platter, sprinkle with kosher salt, and serve with plenty of napkins.