Bring a medium pot of water to a boil. Heat the oil to 340 degrees F in a medium Dutch oven.
Remove all skin, pin bones, blood lines and sinew from the red snapper fillet. Chop as evenly as possible into 1/4-inch cubes and transfer to a medium non-reactive bowl.
Add the lime juice and some salt; cover and refrigerate for 15 to 20 minutes.
Cook the sweet potatoes in the boiling water until tender, about 5 minutes. Drain the sweet potatoes, then mash with the rice wine vinegar and some salt in a medium bowl. Cool in the refrigerator until ready to serve. Stir in 1 tablespoon coconut cream just before serving.
Peel the plantain and use a vegetable peeler to slice the plantain into long, thin strips. Fry the plantain strips in the oil until lightly golden and crisp, about 3 to 4 minutes. Transfer to a paper towel-lined plate and season with salt.
Drain the fish, reserving the lime juice. Add the onion, bell pepper and jalapeno to the lime juice and let sit until slightly softened, about 5 minutes. Drain the vegetables, reserving the lime juice. Combine the fish with the vegetables and add the remaining 1 of tablespoon coconut cream. Season with salt and add the reserved lime juice as needed.
To assemble, spoon the sweet potato puree onto 2 plates, making a shallow well in the center. Place a 3-inch round ring mold in the center and fill with the ceviche. Top with the chopped cilantro and chives, then remove the ring mold. Place a tomato half, cut-side up, on top, then top with 2 fried plantain strips.