To clean the Akoya, rinse in fresh cold water and remove the beard from the base of the Akoya by firmly pulling downward.
Using an oyster shucker, open the fresh Akoya by inserting the blade at the base, cutting through the abductor as close to the shell as possible. Lever open the shell and run the shuck down to opposite shell to release the muscle. Keep the Akoya in the shell and chill on ice until ready to serve.
In a small food processor, blend avocado with juice of 2 limes, seasoning with salt, pepper and tabasco. Blend until smooth.
Peel and segment pink grapefruit and cut into small pieces.
To serve, top each Akoya with small amounts of avocado puree, grapefruit and coriander leaves. Finish with caviar and serve with extra lime wedges to garnish.