Place a serving bowl in the refrigerator so that it is cold when you are ready to serve.
Bring a pot of water to a boil and add the corn cob to the water. Let the corn cook in the boiling water for 3 minutes.
After 3 minutes, remove the corn from the boiling water and plunge it into an ice bath until it has completely cooled off.
Make sure there are no bones or skin attached to the fish.
Cut the fish into 1/4 inch thick slices. Keep cold in the fridge until ready to serve.
Cut the cherry tomatoes into rounds and set aside.
Remove the outer, tough layers of the lemongrass and VERY thinly slice about 2-3 tbsp worth of lemongrass. You will need a sharp knife for this. Set aside.
Cut a wedge of avocado (1/8th of an avocado) and peel it. Cut into 1/3 inch chunks and set aside.
Thinly slice about 1/2 of the Thai bird chili (or as much/little as you like) and set aside.
Coarsely chop the cilantro and set aside. You need about 3-4 Tbsp of cilantro.
Cut about 1/4 cup of corn kernels off of the cob and set aside. Save any remaining corn for another purpose.
Place the sliced fluke in a chilled mixing bowl along with 2-3 Tbsp sliced lemongrass, and 1 tsp of olive oil. Stir gently to combine.
Place the cold coconut leche de tigre in the bottom of the chilled serving bowl. Place the fish (that has been tossed with olive oil and lemongrass) in the center of the bowl and arrange the corn, tomatoes, avocado, and chili on top of the fish. Serve immediately and as cold as possible.