Heat the oven to 425 F. Line a rimmed baking sheet with foil and set a wire rack on top.
Pat the wings very dry with paper towels; surface moisture is what keeps the skin from crisping.
In a large bowl, whisk the baking powder, kosher salt, smoked paprika, garlic powder, onion powder and cayenne. Add the wings and toss until evenly coated.
Arrange the wings skin side up on the rack in a single layer, leaving a little space between them.
Bake 40 minutes, turning the pan once halfway through, until the skin is deep golden and a wing reads 175 F at the thickest part.
While the wings bake, stir the Greek yogurt, lemon juice, dried dill and pinch of salt in a small bowl; chill until serving.
Rest the wings 5 minutes, then pile them on a platter with the celery sticks and the yogurt dip.