Preheat the oven to 425°F (220°C) and set a wire rack inside a rimmed sheet pan.
Pat the wings completely dry with paper towels. Toss with the baking powder, salt, pepper, and garlic powder until evenly coated.
Arrange the wings in a single layer on the rack, leaving space between pieces. Bake for 45 to 50 minutes, flipping halfway through, until deeply golden and crisp.
While the wings bake, combine the tamarind concentrate, brown sugar, soy sauce, garlic, ginger, fish sauce, and sriracha in a small saucepan. Simmer for 5 to 7 minutes, until slightly thickened.
As soon as the wings come out of the oven, toss them in the warm glaze while they're still hot.
Scatter sesame seeds and scallions over the top and serve immediately with lime wedges.