Parts of this recipe goes quickly, so seriously consider getting everything ready before hand.
In a large skillet, heat that oil on medium until it shimmers, add the cumin seeds and onion and cook, stirring until the onions begin to brown.
Add ginger, coriander, cayenne, and turmeric. Stir this around for about 20 seconds.
Add tomatoes. Stir around the tomatoes for about a minute, scraping up any stuck bits. Add salt to taste.
Turn heat to low, cover, and simmer for about 10 minutes.
Add chickpeas and liquid and bring heat to medium heat until the sauce boils.
Once again, lower heat, cover, and simmer for about 15 minutes.
Add garam masala and lemon juice. Then stir and cook uncovered for about 5 minutes.