Place flour in a shallow bowl. Use a meat tenderizer or the bottom of a sturdy cup to pound chicken to about 1/4 inch thick. Season with salt and pepper. Dredge chicken in flour, turning to coat all sides. Heat oil in a medium skillet over medium-high heat. Cook chicken in batches, turning once, until golden brown, 3 to 4 minutes. Transfer to a plate and tent to keep warm. Reserve skillet.