COCKTAIL SAUCE - Combine all the ingredients for the cocktail sauce, and cover and refrigerate until ready to use.
FRITTERS - In a large bowl, combine the flour, baking powder, salt and pepper. In a medium bowl, combine the remaining ingredients (expect the oil). Make a well in the dry ingredients, and add the liquid. Stir with a rubber spatula until just combined.
In a deep, heavy saucepan, heat half of the oil to 375°F/190°C (To test temperature: A small piece of bread dropped into the oil should float up to the surface almost immediately and brown within 45 seconds.).
Drop the fish mixture by spoonfuls into the hot oil. Deep fry the fritters in batches until golden brown, for about 5 minutes. Transfer to a paper towel-lined plate (to absorb excess oil).
Peel and slice the plantain lengthwie as thinly as possible. In a deep, heavy saucepan, heat the remaining oil to 375°F/190°C (Try the bread test again.) Carefully place the plantain strips into the hot oil, frying in batches so they do not stick to one another. With a slotted spoon move the strips around for about 1 minute until they become crsip. Immediatgely remove them and transfer to a paper towel-lined plate. Sprinkle with salt while they are still warm.
To serve, place a Romaine leaf inside a bowl, then top with a couple of the plantain strips. (Placing them against the side of the bowl gives the dish a little height.) Add about 3 seafood fritters. Sprinkle some diced red peppers on top of each fritter.
Serve with Caribbean Cocktail Sauce on the side.