Heat oil in your large sauté pan over medium heat until shimmering, then add the chopped onion. Sauté for 5 minutes until the onion is translucent and fragrant, with a slight golden hue around the edges.
Add the ground cumin, turmeric, and garam masala to the pan. Toast the spices for 30 seconds, stirring constantly, until they release their aromatic oils and turn darker in color.
Stir in the tomato paste and cook for another 2 minutes, stirring constantly. The paste should deepen in color and smell rich and smoky, coating the onions and spices evenly.
Add the drained chickpeas to the pan, stirring well to coat them in the spice and tomato mixture. Cook for 3 minutes, allowing the chickpeas to warm through and absorb flavors.
Pour in the coconut milk, stirring to combine everything into a creamy sauce. Bring the mixture to a gentle simmer and cook uncovered for 10 minutes, stirring occasionally, until the sauce thickens and flavors meld.
Taste the sauce and adjust the salt or spice level as needed. If the sauce thickens too much, add a splash of water or coconut milk. Continue simmering until desired consistency is reached.
Turn off the heat and stir in the chopped fresh cilantro for a burst of herbal brightness. Let sit for 2 minutes to allow the flavors to settle and develop.
Spoon the hot chickpea tikka masala over steamed rice or serve with warm naan. Garnish with extra cilantro if desired, and enjoy this comforting, flavorful dish.