1Combine Riesling, rice vinegar, sugar, and ginger juice in sauce pot and bring to a boil. Remove from heat, add chili pepper flakes, cool to room temperature, and add cilantro.
2In a food processor, mince the ginger and scallions. Add the water chestnuts and pulse until chopped. Transfer to a mixing bowl and add coarsely-chopped snow peas.
3In a separate bowl, beat egg whit until foamy. In the food processor, add 1/2 the shrimp 1/2 the egg white; pulse until the shrimp is finely chopped, not mushy. Remove to bowl and process remaining shrimp and egg white.
4Return all the shrimp and water chestnut mixtures to the food processor. Add cornstarch, soy sauce, salt, sugar, and chili oil. Pulse 3 to mix.
5Place a heaping teaspoon of the shrimp mixture in the center of a won ton skin. With your finger, moisten the edge of the skin with water, fold in half, and pinch the edges firmly together to seal. Then moisten the 2 ends and pinch them together. Place on a baking sheet.
6Bring 5 quarts of slightly salted water to a boil. Add dumplings and stir. When they float to the surface, cook 30 seconds more. Drain.
7Toss dumpling with Riesling sauce, put on platter, and sprinkle with toasted sesame seeds.