In a chilled bowl, mix ingredients together. Mold tuna into small towers either using a pvc pipe, ramekin or cut out can.
Cut 2-inch asparagus spears and save. Take the rest of the asparagus and roughly chop. In a blender, add 1/2 cup chopped asparagus with mustard and juice. Blend at high speed and add oils. Check for seasoning. Toss spears in vinaigrette. Place spears in a flat circle and top with tuna. Drizzle a little of the vinaigrette on the plate. Garnish with sesame seeds.