Place the eggplant in a colander, and sprinkle with about 1/2 tsp salt on the cut surfaces. Allow them to sit and release some of their liquid while you start making the sauce.
In a large nonstick saute pan, heat the oil over medium-low. Add the onion and ginger, and stir frequently until it starts to become fragrant (don't let the onion brown--if it starts to, turn the heat down).
Turn down to low, and add the garlic, curry powder, turmeric, and stir and saute for 1-2 minutes. Then add the tomatoes with their juices and salt, turn the heat up to medium-low, and stir frequently while the tomatoes break down and release more of their juices, about 5-7 minutes.
Gently wipe the salt off of the eggplant. When the tomatoes have become more juicy, add the eggplant, and stir well to combine. Bring to a simmer, and then add chickpeas and coconut milk. Reduce heat to low, cover, and simmer for about 15 more minutes.
Serve the curry with white or brown rice (I like jasmine rice), and garnish with cilantro or parsley, if desired.
See post for substitution ideas.