Heat oil in large pot over medium; sauté onion 5 minutes until starting to soften and turn golden.
Cook garlic and ginger another minute until fragrant.
Add cumin, coriander, paprika, cinnamon, and optional cayenne; toast about 30 seconds.
Add chickpeas, tomatoes with juice, and broth; boil, reduce heat, and simmer 20 minutes to blend flavors.
For creamier, thicker soup, lightly mash about half the chickpeas against pot side with masher or spoon back.
Wilt spinach 2-3 minutes; add lemon juice and season with salt and pepper. Serve hot with cilantro and optional oil drizzle.