In a large pot filled with water, add onion, bay leaf, peppercorns, and salt. Bring to a boil and cook the lobsters, and cook about 8 minutes. Remove the lobsters from the pot and allow them to cool.
Make the dressing: Put all the ingredients into a blender and puree until smooth. Taste and adjust seasoning with salt and pepper.
Pour 2 inches of vegetable oil into a deep pot and heat it to 375 degrees F.
Peel the plantains and slice them into 1/4-inch thick slices on the diagonal. Fry the plantains in batches until they are crispy, about 5 minutes. Drain on paper towels and season them with salt.
Remove the meat from the tails and slice into 1/4-inch slices. Slice hearts of palm into 1/4-inch disks. In a bowl, combine lobster meat, hearts of palm, and onion; add some of the dressing and toss gently to combine; taste and adjust seasoning. Place several plantain slices on a plate and generously pile on the salad. Garnish with cilantro leaves and lime wedges.