In Dutch oven or large heavy-bottomed saucepan, heat oil over medium heat; cook garlic and ginger, stirring, until fragrant, about 1 minute. Add onion, coriander, turmeric and cinnamon; cook, stirring often, until onion is softened, about 5 minutes. Stir in tomato paste; cook for 1 minute.
Add 1-1/4 cups water, broth, celery and carrot; bring to boil. Reduce heat, cover and simmer until celery is softened, about 15 minutes.
Stir in cauliflower, chickpeas, prunes, salt and pepper; bring to boil. Reduce heat, cover and simmer, stirring occasionally, until cauliflower is tender, about 15 minutes.
Meanwhile, stir couscous with 1-1/3 cups boiling water. Cover and let stand for 5 minutes; fluff with fork.
Stir spinach and lemon juice into cauliflower mixture; cook just until spinach is wilted. Serve over couscous; sprinkle with almonds.