In a non-reactive bowl, whisk together all of the ingredients for the lemon coriander vinaigrette but the oil. Slowly drizzle the olive oil while whisking to emulsify. Reserve.
Heat grill to medium-high. Pierce the sunchokes 4-5 times with a skewer or paring knife to prevent bursting while on the grill. While turning frequently, grill the sunchokes on all sides until lightly charred and give to light pressure (20-40 minutes). Remove individually as they are done. Carefully slice the sunchokes open while still hot and push the sides together, exposing the interior. Season while hot with one tsp of the vinaigrette, a pinch of sel gris and a turn of the pepper mill. Reserve.
Maintain grill at medium-high heat. Peel the thick outer layer from the fennel bulb and carefully slice on a mandoline, approximately 2mm thick. Reserve the slices in acidulated ice water (ice water with 1 Tbsp of lemon juice). When ready to grill, remove the fennel from the water and pat dry. Reserve the water. Lightly toss in a bowl with 2 tsp of the olive oil and black pepper. Place the fennel on the hottest part of the grill and allow the fennel to smoke for approximately 1 minute. Turn and cook for an additional 30 seconds. Remove the fennel and quickly plunge into the existing ice water to arrest cooking and refresh. Remove from the water, pat dry and toss in a bowl with the remaining lemon juice and olive oil. Season with salt and pepper to taste. Reserve.
In a non-reactive bowl, combine all of the ingredients but the prawns. Once combined, add the prawns to the bowl and allow to marinate for 20 minutes. Quickly rinse and pat dry. Lightly oil and grill over medium-high heat for 2-3 minutes per side. Remove from the grill, plate and allow to chill in the refrigerator for at least 5 minutes. Cover and reserve.
For the popped quinoa, rinse quinoa under cold water and drain. In a medium sauce pot over high heat, add the quinoa and water. Bring to a boil, then cover and reduce heat to medium-low. Cook for 15-20 minutes or until there is a white edge. Drain and discard any remaining liquid. Dehydrate the quinoa on a Silpat lined baking sheet (or silicone baking mat) in a low oven or food dehydrator at 145 degrees for 2-3 hours. Heat the oil in a fryer or small sauce pan with high sides to 375 degrees. Fry the quinoa for 15-20 seconds and drain on paper towels. Quinoa may be prepared the day prior.
Peel the center of the prawns, leaving the head and tail on. Toss the prawns, sunchokes, arugula, fennel, quinoa and remaining vinaigrette together in a bowl. On a plate, place a few leaves of the arugula and fennel salad topped with one sunchoke. Arrange two prawns over each of the plated sunchokes and garnish with the remaining salads, caviar, bronze fennel and blanched corn kernels. Season with sel gris and fresh black pepper.