Preheat oven to 400F and line a large sheet pan with parchment paper. Carefully cut pumpkin in half, remove seeds, and place cut-side down on prepared sheet pan. Roast pumpkin at 400F 15 minutes until exterior is slightly softened.
Remove pumpkin from oven and transfer to a cutting board. Carefully remove skin from pumpkin and dice pumpkin into 1/2-inch cubes.
Toss pumpkin cubes with 2 tablespoons vegetable oil and salt and pepper to taste on sheet pan until evenly coated. Return pan to oven and bake pumpkin at 400F 15-20 minutes until pumpkin is tender. Remove from oven.
Place 1-1/2 cups roasted pumpkin cubes and 1/4 cup water in a food processor and process until pumpkin is a smooth puree. Set aside.
Heat remaining oil in a large skillet or Dutch oven over medium-high heat. Add onion and sweet pepper to pan, season with salt and pepper, and sauté until crisp-tender.
Add garlic, ginger, and spices to vegetables and cook 1-2 minutes until fragrant. Add pureed pumpkin, chickpeas, diced tomatoes, and coconut milk to pan and bring to a simmer.
Reduce heat to medium-low and allow curry to simmer 15-20 minutes to allow the flavors to meld, stirring occasionally. Stir roasted pumpkin cubes and spinach into curry until wilted.
Season curry with salt and pepper to taste and serve warm over rice with cilantro, pepitas, lime wedges, and naan. Enjoy!