3/4 pound boneless, skinless chicken thighs (about 2 large), cut into 3/4- to 1-inch pieces
1 large egg white
2 tablespoons Chinese rice wine or dry sherry
1 tablespoon plus 2 teaspoons cornstarch
5 teaspoons low-sodium soy sauce
Kosher salt
1 tablespoon sugar
Freshly ground black pepper
4 tablespoons peanut or vegetable oil
2-inch piece ginger, sliced paper thin
5 scallions, whites cut into 1/2-inch pieces and greens sliced, separated
5 scallions, whites cut into 1/2-inch pieces and greens sliced, separated
2 red bell peppers, sliced
1 cup frozen corn kernels
Cooked brown rice, for serving