Steam sweet potato, covered, 5 minutes or until tender, and cool. Combine chutney and next 6 ingredients (chutney through garlic) in a large bowl; stir well with a whisk. Add sweet potato, 1/4 cup onions, and beans; stir well to coat. Place 1 cup spinach on each of 3 plates; top with 2/3 cup bean mixture. Sprinkle evenly with 1/4 cup onions.