In a pot over medium heat, cook onion in oil until tender, about 6 minutes. Stir in carrots, turmeric, and salt. Add 10 cups water, bring to a boil, then simmer, 30 minutes. Add beans and cook until just tender, about 2 minutes.
To serve, fill a bowl with spinach and dill. Ladle 3 cups hot soup over greens, cover with a plate, and let steep 5 minutes. Add lemon juice.