Meanwhile, heat oil in large nonstick skillet on medium-high heat. Add cauliflower and onions; cook 15 min. or until onions are caramelized, stirring occasionally. Add garlic and crushed pepper; cook 1 min., stirring frequently. Add spinach; cover. Cook 5 min. Stir in beans; cook, covered, 2 min. or until spinach is wilted and beans are heated through.