Meanwhile, make sauce. In 10-inch nonstick skillet, heat 1 tablespoon olive oil over medium heat until hot. Reduce heat to low; add 1/4 cup onion and bell pepper. Cook, stirring frequently, until vegetables are crisp-tender. Add remaining sauce ingredients. Heat to boiling; reduce heat to medium. Simmer uncovered 7 to 9 minutes, stirring frequently. Reduce heat to medium-low; simmer until tomatoes are soft and sauce is thickened.