Preheat oven to 450°F. Toss together cauliflower and 1 tablespoon of the oil on a large rimmed baking sheet until florets are coated; spread in a single layer. Bake until florets are browned, about 20 minutes. Set aside.

Meanwhile, process coconut, lemon juice, jalapeño, ½ cup coconut milk, 2 cups cilantro, and ½ tablespoon ginger in a blender until smooth, about 30 seconds. Transfer to a small bowl; set aside. Rinse blender clean, and set chutney aside.

Heat remaining 3 tablespoons oil in a large skillet over medium until shimmering. Add onion, and cook, stirring occasionally, until browned on edges, 6 to 7 minutes. Stir in garlic, salt, and remaining 1 tablespoon ginger; cook, stirring constantly, until fragrant, about 30 seconds. Add cumin, coriander, smoked paprika, cayenne, and garam masala; cook, stirring constantly, until spices are fragrant, about 30 seconds.

Stir diced tomatoes and tomato paste into mixture in skillet; cook, stirring often, until well combined. Pour tomato mixture and water into blender. Secure lid, and remove center piece to allow steam to escape. Place a clean towel over opening; process until smooth, about 30 seconds.

Transfer blended mixture to skillet. Stir in chickpeas, and cook over medium-high until sauce starts to bubble, about 2 minutes; continue to cook until chickpeas are warmed through, about 2 minutes. Stir in remaining 1 ¼ cups coconut milk, and return to a boil over medium-high. Stir in roasted cauliflower and remaining ¼ cup cilantro; simmer over medium until sauce slightly thickens, about 3 minutes. Serve hot with naan and chutney. Garnish with additional cilantro, and serve.