PreparationMake filling: Lightly whisk egg white in a large bowl, then whisk in ginger, garlic, peanut oil, sesame oil, soy sauce, cornstarch, sugar, and salt. Add jicama, scallion, and pork and mix together with your hands until combined well. Assemble dumplings: Separate wonton wrappers and restack in piles of 10. Cut through each stack with cookie cutter and discard trimmings. Arrange 6 rounds on a work surface (keep remaining rounds covered with plastic wrap) and mound a scant tablespoon filling in center of each. Lightly moisten edge of wrappers with a finger dipped in water. Working with 1 at a time and leaving dumpling on flat surface, gather edge of wrapper around side of filling, pleating wrapper to form a cup and pressing pleats against filling (leave dumpling open at top). Flatten filling flush with edge of wrapper with wet finger and transfer dumpling to a tray. Make more dumplings in same manner with remaining rounds and filling. Steam dumplings: Generously oil bottom of colander-steamer insert and bring a few inches of water to a boil in pot so that bottom of insert sits above water. Arrange 10 dumplings, about 1/2 inch apart, in insert and steam over moderate heat, covered, until dough is translucent and filling is just cooked through, about 6 minutes. Stir together black and white sesame seeds and sprinkle over dumplings. Serve immediately. Cooks' note:·Dumplings (without sesame seeds) can be formed and steamed 1 day ahead and cooled completely, then chilled, covered. Steamed dumplings can also be frozen 1 week; freeze in 1 layer on a plastic-wrapped tray until hardened, then transfer to a sealable plastic bag. Reheat (do not thaw if frozen) in colander-steamer insert over simmering water (over low heat) until heated through, about 6 minutes.
PreparationMake filling: Lightly whisk egg white in a large bowl, then whisk in ginger, garlic, peanut oil, sesame oil, soy sauce, cornstarch, sugar, and salt. Add jicama, scallion, and pork and mix together with your hands until combined well. Assemble dumplings: Separate wonton wrappers and restack in piles of 10. Cut through each stack with cookie cutter and discard trimmings. Arrange 6 rounds on a work surface (keep remaining rounds covered with plastic wrap) and mound a scant tablespoon filling in center of each. Lightly moisten edge of wrappers with a finger dipped in water. Working with 1 at a time and leaving dumpling on flat surface, gather edge of wrapper around side of filling, pleating wrapper to form a cup and pressing pleats against filling (leave dumpling open at top). Flatten filling flush with edge of wrapper with wet finger and transfer dumpling to a tray. Make more dumplings in same manner with remaining rounds and filling. Steam dumplings: Generously oil bottom of colander-steamer insert and bring a few inches of water to a boil in pot so that bottom of insert sits above water. Arrange 10 dumplings, about 1/2 inch apart, in insert and steam over moderate heat, covered, until dough is translucent and filling is just cooked through, about 6 minutes. Stir together black and white sesame seeds and sprinkle over dumplings. Serve immediately. Cooks' note:·Dumplings (without sesame seeds) can be formed and steamed 1 day ahead and cooled completely, then chilled, covered. Steamed dumplings can also be frozen 1 week; freeze in 1 layer on a plastic-wrapped tray until hardened, then transfer to a sealable plastic bag. Reheat (do not thaw if frozen) in colander-steamer insert over simmering water (over low heat) until heated through, about 6 minutes.