Gong Bao Doufu Kung Pao Tofu

Name: Gong Bao Doufu (Kung Pao Tofu)
Ingredients: 1 tablespoon soy sauce; 1 tablespoon dark soy sauce; 1 tablespoon Chinkiang (Chinese black) vinegar; 1 tablespoon granulated sugar; 3 tablespoons plus 1 teaspoon cornstarch, divided; 1 pinch salt; 14 to 16 ounces firm tofu (depending on package size), drained; Neutral oil (such as vegetable or canola), for cooking; 1 (3-inch) pieces ginger, peeled and minced; 3 dried chiles (such as Thai or serrano), halved; 3 garlic cloves, thinly sliced; 2 scallions, green parts roughly chopped, white parts finely chopped; 1 teaspoon toasted, crushed Sichuan peppercorns (optional); 2 tablespoons unsalted or salted roasted peanuts; Cooked rice, for serving