Heat a large heavy saucepan over medium-high heat.
Add oil to pan; swirl to coat.
Add shallots; saut 3 minutes or until softened, stirring occasionally.
Add garlic and ginger; saut 1 minute.
Add 2 cups water, coconut milk, salt, red pepper, and squash; bring to a boil. Cover, reduce heat, and simmer 20 minutes or until squash is tender, stirring occasionally.
Place squash mixture in a blender.
Remove center piece of blender lid (to allow steam to escape); secure blender lid on blender.
Place a clean towel over opening in blender lid (to avoid splatters). Blend until smooth. Stir in juice.
Garnish with additional pepper and cilantro leaves, if desired.