In large stock pot, heat oil over medium heat. Add onion, garlic and ginger, and cook, stirring frequently until softened and just beginning to brown around edges, about 4 minutes. Stir in chile and pumpkin purée, and whisk in water or stock. Bring to boil, reduce heat and simmer on low, giving an occasional stir, for 20 minutes or until slightly reduced and thickened. Remove chile after soup simmers if you don't care for much spice.
Add coconut milk, agave or honey (if using), and peanut butter to pot. Using an immersion blender or working in batches in standing blender, purée soup until smooth. Season with salt and keep warm over low heat. Do not allow soup to simmer or boil at this point. (This reduces risk that oils in peanut butter will separate and break soup's smooth texture.)
Divide soup between bowls, sprinkle with scallions chives and dollop with crème fraîche or yogurt, or a drizzle of olive oil to make it vegan. Serve with warm crusty baguette or chunks of warm sourdough for dipping.