Press the extra-firm tofu for at least 30 minutes to remove excess water. Cut into 1-inch cubes.

In a shallow dish, combine cornstarch, all-purpose flour, 1/2 teaspoon salt, 1/4 teaspoon white pepper, and Chinese five-spice powder (if using).

Lightly toss the tofu cubes in the cornstarch mixture, ensuring they are evenly coated. Set aside.

To make the salt and pepper blend: In a dry pan, toast Sichuan peppercorns over medium heat for 2-3 minutes until fragrant. Grind them into a fine powder using a mortar and pestle or a spice grinder. Mix the ground Sichuan peppercorns with coarse sea salt, garlic powder, and onion powder. Set aside.

Heat vegetable oil in a large skillet or wok over medium-high heat. Once hot (around 350°F / 175°C), carefully add the coated tofu in batches, ensuring not to overcrowd the pan. Fry for 3-5 minutes per side, or until golden brown and crispy. Remove with a slotted spoon and place on a wire rack lined with paper towels to drain excess oil.

Once all tofu is fried, remove most of the oil from the pan, leaving about 1 tablespoon. Add minced garlic and sliced red chili (if using) and stir-fry for 30 seconds until fragrant.

Return the crispy tofu to the pan. Sprinkle generously with the prepared salt and pepper blend. Toss gently to coat evenly.

Garnish with chopped green onions and serve immediately.