Reserve 2 tablespoons of the coconut milk for drizzling when serving.
In a 4- to 6-quart slow cooker, combine the remaining coconut milk, vegetable stock, butternut squash, carrots, shallots, garlic, ginger, red curry paste, and 1 tablespoon of kosher salt.
Cook on high for 4 hours, or on low for 6 hours, until all vegetables are tender and fully cooked.
Once cooked, stir in the lime zest and juice. Purée the mixture with an immersion blender until silky and smooth, or transfer in batches to a standard blender.
Ladle the soup into bowls, drizzle with the reserved coconut milk, and finish with a sprinkling of chopped cilantro.