Heat olive oil in a large pot over medium heat. Add diced onion, carrot, and celery and sauté until softened, about 5 minutes. Stir in minced garlic and fresh ginger and cook for 1-2 minutes until fragrant. Add the ground cumin, coriander, smoked paprika, dried thyme, and turmeric; stir well to coat the vegetables with spices. Pour in the black beans, diced tomatoes, pumpkin puree, and vegetable stock. Bring the mixture to a boil, then reduce heat and simmer for 20 minutes to allow flavors to meld. Use an immersion blender to partially blend the soup for a creamy texture while keeping some bean chunks for bite. Stir in the coconut milk and lime juice, heating through without boiling. Season with salt and freshly ground black pepper to taste. Serve hot, garnished with fresh coriander on top.