To make Cucumber Gelée, in bowl, combine all ingredients except gelatin. Steep 5 hours; strain. Soak gelatin in cold water 5 minutes; squeeze out water. In small pan, heat 3/4 cup cucumber juice just until warm. Add gelatin; stir until dissolved. Add to remaining cucumber juice; mix well. Transfer to storage container; chill overnight or until set. (Yield: 2 cups)
To make Yuzu Aioli, in blender, purée all ingredients except mayonnaise. Transfer to bowl, whisk in mayonnaise. Chill. (Yield: 3 cups)
To make Lobster Salad, dry lobster meat well on paper towels. Place in bowl, add green onions, cucumber, shiso and 11/2 teaspoons salt; mix gently. Add Yuzu Aioli; mix until combined. Add avocado and sprinkle with remaining salt; fold in. (Yield: 3 pounds)
For each serving, to order, place 2 1/2-inch ring mold in small bowl. Fill mold with 2 ounces Lobster Salad; pack down well and remove mold. Spoon 1 tablespoon Cucumber Gelée around Lobster Salad; garnish with peppercress, celery leaf, shiso and lemon zest.
Recipe by Chef Tim Cushman (o ya , Boston, MA)