Heat oil in a large nonstick skillet over medium heat.
Add onion and green bell pepper; saut 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. Set aside, and keep warm.
Steam cauliflower 4 minutes or until crisp-tender. Spoon cauliflower onto serving plates; top with sauce.