Stir together superfine sugar, fish sauce, oyster sauce, tamarind water, lime juice, chile, and garlic in a small bowl. Set aside. Make the pad thai:

Soak noodles in boiling water according to package directions. Drain. Transfer to a medium bowl. Add 1 tablespoon oil, and toss to coat. Set aside.

Heat 1 tablespoon oil in a large stainless steel skillet over high. Add mushrooms and ½ teaspoon salt; cook, stirring occasionally, until mushrooms are tender and golden brown, 3 to 5 minutes. Transfer to a small bowl; set aside. Wash and dry skillet.

Return skillet to heat over medium-high, and add 2 tablespoons oil. Add tofu slices to hot oil in a single layer; sprinkle evenly with ⅛ teaspoon salt. Cook, undisturbed, until golden on bottom, 1 minute and 30 seconds to 2 minutes. Carefully flip using a thin metal spatula. Sprinkle evenly with remaining ⅛ teaspoon salt. Cook until golden brown on other side, 1 minute and 30 seconds to 2 minutes. Transfer to a plate lined with paper towels. Set aside. Wipe skillet clean.

Return skillet to heat over medium-low, and add 1 ½ teaspoons oil. Add peanuts, and sprinkle with salt to taste. Cook, stirring constantly, until peanuts are fragrant and toasted, 1 to 2 minutes. Transfer to a mortar, and coarsely grind using a pestle. (Alternatively, transfer to a cutting board, and finely chop.) Set peanuts aside, and wipe skillet clean.

Return skillet to heat over high, and add remaining 1 ½ teaspoons oil. Add eggs; cook, undisturbed, until bubbly and mostly set, about 15 seconds. Scramble eggs, and break into large pieces; push scrambled eggs to back edge of skillet. Add Chinese chives and ⅔ cup bean sprouts to center of skillet. Cook, stirring constantly, until softened, about 30 seconds. Add noodles and half of the sauce (about ¼ cup). Cook, stirring constantly, until ingredients in skillet are well incorporated and noodles have separated into individual strands, about 30 seconds. Stir in cooked mushrooms, tofu, and remaining sauce (about ¼ cup). Cook, stirring constantly, until well combined and noodles are shiny and well coated, about 20 seconds. Immediately divide noodle mixture between 2 bowls. Top evenly with ground peanuts, cilantro, and remaining ⅓ cup bean sprouts.