In a large, deep skillet, heat the olive oil and garlic over moderate heat until the edges of the garlic begin to turn golden, about 3 minutes. Add the crushed red pepper and cook for 30 seconds. Add the Swiss chard stems and cook over moderately high heat until tender, about 5 minutes. Add the Swiss chard leaves and cook, stirring frequently, until wilted, about 4 minutes. Season with salt and serve.