Shrimp and Shiitake Gyoza

Name: Shrimp-and-Shiitake Gyoza
Ingredients: 1/4 cup plus 1 tablespoon vegetable oil; 4 ounces shiitake mushrooms, stems discarded and caps thinly sliced; 4 ounces asparagus, thinly sliced crosswise; 1 medium shallot, sliced; 1 pound shelled and deveined shrimp; 4 tablespoons oyster sauce; 2 tablespoons chopped cilantro; 1 scallion, finely chopped; 1/2 teaspoon kosher salt; One 10- to 12-ounce package gyoza wrappers