In a food processor, mix goat cheese, salt and pepper until cheese is soft. Place in a pastry bag.
Mix grapeseed oil with lime juice, herbs and pink peppercorns. Using three separate bowls, toss grapeseed oil mixture with tuna, galia melon and watermelon.
To assemble: Place ring mold on a flat surface. Place 1 ounce of diced tuna on the bottom. Top with 1/2 ounce of goat cheese. Continue with 1 ounce of galia melon followed by 1/2 ounce of goat cheese. Complete the last layer with diced watermelon and carefully remove ring mold. Finish with a dollop of goat cheese, a drizzle of Extra Virgin Olive Oil and herbs.