Pound chicken to 1/4-inch thick between plastic wrap or in large food storage bag. Season with salt and pepper and dress with fennel, oregon and chili flakes.
Heat a tablespoon of olive oil in large, cast-iron skillet over medium-high heat. Add chicken skin-side down and crisp skin, pressing down with spatula while skin browns, about 5 minutes. Turn chicken and cook 5 minutes more pressing down with a spatula to keep the breasts from shrinking up too much. Remove to a warm platter and cover with loose foil.