Heat the oil in a large stockpot and brown the onion. Add the smoked fish, the tomato paste, and 1/4 cup of the salted water. While the onion mixture is browning, prepare the stuffing for the sea bass steaks by placing the parsley, garlic, chile, and scallions in a food processor and pulsing until they form a thick paste. When the paste is ready, score the sea bass steaks and poke the stuffing into the slits.
Place the sea bass in the stockpot with the onion mixture, allow it to cook for 5 minutes, and add the remaining water. When the fish mixture comes to a boil, cover the pot, lower the heat, and add the vegetables in the order given, finishing off with the pricked habanero chile, which you will remove (and reserve) when the thiebou dienn is spicy enough for you. Cook for 20 minutes. Remove the sea bass steaks keeping them whole, and place them on a serving platter. Cover them with a bit of the cooking liquid, and keep them warm.
Continue cooking the thiebou dienn for an additionaly 15 minutes, then remove the vegetables and arrange them on a platter and keep them warm. Reserve 2 cups of the cooking liquid to make the sauces. Return the remaining liquid to a boil, add the rice, cover, and cook for 20 minutes, or until the liquid is absorbed and the rice is done.
While the rice is cooking, pulverize the habanero chile that you have reserved and add it to 1 cup of the reserved cooking liquid. Heat it, stirring occasionally, and place it in a sauceboat. Heat the remaining cup of reserved cooking liquid and place it in a separate sauceboat. This will give you a regular sauce and a fiery hot one.
When ready to serve, mound the rice on one platter and the fish and vegetables on another. Alternatively, you can place the rice in a large basin or deep dish and arrange the vegetables and fish on top and eat Senegalese-style with your hands (right hand only, please!) or with a large spoon.