Heat the oil a large, deep Dutch oven or heavy pot over medium-high heat. Add the onion and cook for about 5 minutes, or until the onion is beginning to brown. Add the garlic and ginger and cook for 3 minutes, stirring frequently.
Add the chickpeas and cook over high heat for a few minutes, until the chickpeas are beginning to turn golden and they are coated with the onion and garlic mixture.
Toss in the spinach, one handful at a time. This will take about 5 minutes; stir in a handful or two and wait for it to wilt down and make room in the pot before adding the next handful. When all the spinach has been added, pour in the coconut milk, salt, ground ginger, and lemon juice. Bring to a simmer, then turn down the heat and cook for 10 minutes, or until the chickpeas are warmed through. Taste and add more salt and lemon juice, if necessary.