Heat the coconut oil in a large saucepan over medium-high heat, stir in the shallots and a couple generous pinches of salt, and sauté until soft. Stir in the green curry paste along with a dollop of cream from the top of the coconut milk. Stir well, and sauté for another minute or so, until fragrant.
Stir in the zucchini with another couple of pinches of salt, and sauté, being careful not to brown, until the zucchini is tender 5-7 minutes, or so. Add the remaining coconut milk and the water, let everything come up to a simmer, and remove from heat. Season the soup with the juice of lime, and salt to taste. It's all about balance here, and the soup should be brothy with strong coconut-lime flavor.
Serve over a scoop of brown rice, topped with any (or all!) of the toppings suggested, or experiment with your own ideas.