Steamed Pork and Jícama Dumplings

Name: Steamed Pork and Jícama Dumplings
Ingredients: 1 large egg white; 2 tablespoons minced peeled fresh ginger; 1 tablespoon minced garlic; 1 tablespoon peanut or vegetable oil; 1 tablespoon Asian sesame oil; 1 tablespoon soy sauce; 1 tablespoon cornstarch; 2 teaspoons sugar; 1/2 teaspoon salt; 1 cup diced (1/4 inch) peeled jicama; 1/2 cup minced scallion; 1 1/2 pound ground pork (not lean); 60 wonton wrappers (from two 12- to 14-ounce packages), thawed if frozen; 2 tablespoons black sesame seeds, toasted; 2 tablespoons white sesame seeds, toasted; Special equipment: a 2 1/2-inch round cookie cutter; a pasta pot with a deep perforated colander-steamer insert or a metal steamer; Accompaniment: soy dipping sauce