In a small, heavy saucepan, bring the rice, coconut milk, butter and 1 cup cold water to a boil. Cover, lower the heat and simmer, undisturbed, until the rice is tender, about 15 minutes. Fluff the cooked rice with a fork and keep warm.
Meanwhile, heat a griddle or 2 heavy skillets over medium-high heat. Season the fish on both sides with salt and the jerk seasoning. Lightly salt both sides of each pineapple ring. Drizzle the olive oil in the pan, add the fish and pineapple rings and cook until golden, about 3 minutes on each side.
Chop 2 pineapple rings into small cubes; stir into the rice along with the peas. Season with salt and pepper. Arrange a pineapple slice, a fish fillet and rice on each plate. Garnish with lime wedges.
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