Heat oil in a skillet over moderate heat.
Add the onions, ginger, and garlic. Simmer until fragrant, stirring often to prevent browning; about 2 minutes.
Add the chickpeas and drained tomatoes. Simmer for about 5 minutes, stirring occasionally.
Add the torn up spinach and cook until it's wilted down. Depending on the size of your skillet, you may want to add one handful at a time.
Add the coconut milk, curry paste, curry powder, turmeric (if using), and salt. Stir until the paste has dissolved and the seasonings have mixed in well. This may take about 2-3 minutes of constant stirring and folding.
Let the curry simmer for about 10 minutes, stirring occasionally.
Remove from heat and serve with warm naan, pitas, rice, or on its own.