Thaw the dough sheets.
Soak the shiitake mushrooms according to the package directions. Rinse and trim scallions and cut into thin rings.
Rinse the chicken, pat dry, and finely chop. Remove corn kernels from the cob. Drain mushrooms, chop finely and mix with the chicken, corn, and scallions. Season with ginger, soy sauce, and cayenne pepper. Cut tops of scallions into thin strips. Place about 2 tablespoons of the filling on each sheet of dough. Brush the edges of the dough with egg white and gather upwards to make a purse. Secure by tying a strip of scallion around the top. Set the wontons in a bamboo steamer and steam over a pot or wok of boiling water, covered for about 10-12 minutes. Serve alongside your favorite Asian dipping sauces.