Preheat oven to 400°F. Brush a large rimmed baking sheet with oil; set aside.

Whisk together flour, cornstarch, onion powder, cinnamon, salt, smoked paprika, and black pepper in a wide shallow bowl or baking dish until fully combined. In a second bowl or baking dish, whisk together eggs and lemon zest and juice until fully combined.

Thoroughly pat chicken pieces dry with paper towels. Working with 1 chicken piece at a time, dredge both sides of chicken in flour mixture, tapping off any excess. Dip both sides of chicken in egg mixture, allowing excess to drip off, then return chicken once more to flour mixture, making sure to evenly coat both sides and tap off any excess flour. Place coated chicken on prepared baking sheet, and repeat procedure with remaining chicken pieces.

Evenly dot and brush the top of each chicken piece with oil, being careful not to remove the flour coating. Bake in preheated oven, flipping chicken pieces once halfway through bake time, until golden brown and crisp and a digital thermometer inserted into thickest portion of chicken thighs registers at least 165°F, 35 to 40 minutes. Remove from oven, and let chicken rest a few minutes before serving. Serve hot with lemon wedges.