Combine onion, garlic, hot sauce, salt, and 2 teaspoons black pepper in a large bowl. Add the cold buttermilk and stir to dissolve. Snip the wing tips with kitchen shears if desired. Add the chicken wings and be sure they are all coated well in buttermilk. Cover the bowl and chill for at least 2 hours, or up to 4 hours.
Prepare the seasoned flour by whisking together flour, kosher salt, paprika, garlic powder, onion powder, lemon zest, black pepper, oregano, cayenne, baking powder, sage, and dry mustard. Drain off excess buttermilk and dredge the wings in the flour. Place each batch of dredged wings on a wire rack as you go.
Let wings sit for 10 to 15 minutes.
Meanwhile, heat peanut oil in a deep-fryer or large saucepan to 375 degrees F (190 degrees C).
Carefully drop the chicken wings into the hot oil, 4 or 5 at a time. Fry until golden, crisp, and no longer pink in the centers, about 5 minutes. Drain excess oil from wings on paper towels and lightly season with a pinch of salt while still hot. Continue with remaining wings.