Make wontons (through step 2).Transfer to an oiled plate, and cover with a damp towel to keep moist.
In a 12-inch nonstick skillet with a tight-fitting lid, heat 1 tablespoon oil over medium-high heat. Add half the wontons and cook, turning once, until lightly browned, about 1 minute per side. Carefully add 1/2 cup water (oil may sputter), cover, and steam until translucent and just cooked through, 2 to 3 minutes. Repeat with remaining tablespoon oil and wontons. Sprinkle pot stickers with scallions, if using, and serve with soy sauce.