Heat 1 tablespoon of oil in a large skillet over medium-high heat. Add the diced onion and cook for 1 to 2 minutes, until fragrant. Mix in the chili powder.
In a food processor pulse the garlic cloves, ginger, remaining 1 tablespoon of oil, coriander, cumin, and garam masala.
Add the tomato paste to the food processor and pulse until just mixed in.
Add the cooked onions and continue to process until grainy paste-like consistency forms (if the paste is too thick add an additional tablespoon of oil).
Place the paste into the skillet and cook for 2 minutes to bring out the flavor, stirring occasionally, so it doesn't burn or stick.
Add the chickpeas and crushed tomatoes, simmer for about 5 minutes until the sauce is reduced down by about 1/4.
Pour in the coconut milk and 1/4 cup of water and cook for 5 more minutes.
Stir in the coriander and spinach and continue cooking for about another minute until the spinach has wilted.