PreparationMake jelly: Bring water, mung-bean starch, and salt to a boil in a 2- to 3-quart heavy saucepan, then boil over moderate heat, stirring constantly, until mixture is very thick and translucent, about 3 minutes. Transfer to an 8-inch square baking dish and cool to room temperature, about 45 minutes. Cover surface with plastic wrap and chill until jelly is firm, about 2 hours. Make sauce: Stir together soy sauce, vinegar, sugar, oils, ginger, and garlic in a large bowl until sugar is dissolved. Assemble dish: Run a thin knife around side of jelly to loosen, then unmold onto a cutting board. Cut jelly into 3 strips, then cut each strip crosswise into 1/4-inch-thick slices. Carefully transfer to sauce in bowl, then gently stir in scallions and daikon. Serve with Sichuan-pepper oil and red-chile oil on the side. Cooks' note:Jelly can be chilled up to 1 day.