Preheat the oven to 400°F (200°C).
Sprinkle the eggplant slices with salt and let them sit for about 30 minutes to draw out moisture. Rinse and pat dry.
In a large skillet, heat 2 tablespoons of olive oil over medium heat. Add the onion and garlic, sautéing until the onion is translucent.
Add the bell pepper and cook for another 3-4 minutes until softened.
Stir in the chickpeas, diced tomatoes, cumin, cinnamon, paprika, black pepper, and cayenne pepper (if using). Simmer for about 10 minutes, allowing the flavors to meld.
While the chickpea mixture simmers, brush the eggplant slices with the remaining olive oil and arrange them on a baking sheet. Roast in the oven for 20-25 minutes, flipping halfway through, until golden brown.
In a small bowl, whisk together tahini, water, and lemon juice until smooth.
In a large baking dish, layer half of the roasted eggplant, followed by the chickpea mixture, and then the remaining eggplant on top. Drizzle the tahini sauce over the top.
Bake in the oven for 15-20 minutes until heated through.
Garnish with fresh parsley before serving.