Heat oil over medium heat in a soup pot. Add onions and sauté for about 5 minutes. Stir in ginger & garlic, and cook for about 1 minute. Stir in salt, curry powder, and cayenne pepper. Stir for 1 minute.
Add in carrots and cook for 1 minute. Stir in water and simmer for 20 minutes, stirring occasionally.
Remove from heat and use an immersion blender to blend soup, or carefully transfer mixture to a blender {leaving the top ajar to allow steam to escape} and blend. Simmer soup for another 5-10 minutes to let it thicken a little.
Stir in coconut milk and cook until soup is warmed through - you don't really want this to boil.
Serve with desired toppings.
Notes
*Based on a recipe from Vegetarian Times*Use less cayenne pepper or omit for a more mild soup