Heat 2 teaspoons oil in a large nonstick skillet over medium-high heat. Add onion; sauté 5 minutes. Add broth and next 5 ingredients (broth through red pepper), and bring to a boil. Reduce heat, and simmer 5 minutes.
Place 1/2 cup chickpeas in a food processor; process until minced. Add minced chickpeas and remaining chickpeas to onion mixture. Bring to a boil; reduce heat, and simmer 10 minutes.
Heat remaining 2 teaspoons oil in a Dutch oven over medium-high heat. Add garlic, and sauté 30 seconds. Add spinach; sauté 3 minutes or until spinach is just wilted.
Spoon 1/2 cup spinach mixture onto each of 4 plates. Top each serving with 3/4 cup chickpea mixture; dollop each serving with 2 tablespoons yogurt.