Heat oil in a wok to 350°F. Whisk together 1/2 cup cornstarch, flour, baking powder, and 1 teaspoon kosher salt. Add water and vodka and whisk until a smooth batter is formed, adding up to 2 tablespoons additional water if batter is too thick. It should have the consistency of thin paint and fall off of the whisk in thin ribbons that instantly disappear as they hit the surface of the batter in the bowl.
Add tofu and carefully turn to coat. Working one at a time, lift one piece and allow excess batter to drip off. Carefully lower into hot oil. Repeat with remaining tofu until wok is full. Fry, using a metal spider or slotted spatula to rotate and agitate pieces as they cook until evenly pale golden and crisp all over, about 6 minutes. Transfer to a paper towel-lined plate. Repeat until all tofu is fried. Carefully pour oil out of wok into a heatproof container and reserve.
Combine stock, soy sauce, bean paste, vinegar, sugar, and remaining 2 teaspoons corn starch in a small bowl. Set aside. Combine scallion whites, garlic, and ginger in a second small bowl. Set aside. Coarsely grind half of peppercorns in a mortar and pestle or spice grinder.
Set a fine mesh strainer over a heatproof bowl or saucepan. Return 1/4 cup of the reserved oil to wok and heat over medium-high heat until shimmering. Add remaining half of peppercorns and chilies and cook, stirring, for 5 seconds. Immediately drain through fine mesh strainer. Pick out chilies and set aside. Discard cooked peppercorns.
Return infused oil to the wok and heat over high heat until lightly smoking. Add leeks, celery, and long pepper and cook, stirring and tossing, until vegetables are lightly charred and tender-crisp, about 1 1/2 minutes. Clear a space in the center of the wok and add the scallion/ginger/garlic mixture. Cook, stirring, until fragrant, about 30 seconds. Add peanuts, dried chilies, and drained tofu. Stir sauce mixture and add to wok. Cook, tossing and folding ingredients together until tofu is fully coated. Add scallion greens and ground peppercorns and toss to combine. Serve immediately with white rice.