Heat oil in a large nonstick skillet over medium heat. Add onion and green bell pepper; sauté 6 minutes or until tender. Add garlic; cook 30 seconds. Add tomatoes and next 7 ingredients; stir well. Bring to a boil; reduce heat, and simmer, uncovered, 10 minutes or until thick. Keep warm.
Steam cauliflower 4 minutes or until crisptender. Spoon cauliflower onto serving plates; top with sauce.