Place damp kitchen towel on a stable work surface. Using the back of a heavy knife, whack a coconut along its circumference while rolling and rotating it along the toweled surface until it starts to slit open. To catch the water, give the coconut its last whack in a heavy bowl. once open , pat dry insides of coconuts, then cover and refrigerate.
Place jalapeno, ginger, lobster stock, sugar, lime juice and coconut milk in a blender and puree until smooth.In a nonreactive bowl, toss lobster with the pureed mixture. Sprinkle with red onion, 1/4 cup shaved coconut, green onions, chives and cilantro. Place mixture in coconut halves, dividing equally, and garnish with plantain slices, bell pepper, watercress leaves, and 2 cups shaved coconut.