Set the sauté pan over medium-high heat and add the onion and the 2 tablespoons flour. Sauté, stirring frequently, for 10 minutes, or until lightly browned. Add the garlic and stir for 2 to 3 minutes. Add the wine and stir to scrape up the browned bits from the bottom of the pan. Increase the heat to high and add the tomatoes and pepper to taste. Cook, stirring frequently, for 10 to 15 minutes, until some of the tomato liquid evaporates.