Put greens, cheese, walnuts, garlic, salt, and pepper in a food processor. As machine is running, drizzle in extra virgin olive oil and continue processing until thick and chunky sauce develops.
Rub salmon halves with remaining oil, then season with salt and pepper. Sear salmon pieces in a hot oven-proof pan until a brown crust forms on one side (approximately two minutes); flip and brush seared sides with glaze. Put pan in a 400 degree F oven for another six to eight minutes (to your preferred degree of doneness).
Serve salmon with pesto and edible petals/microgreens (to garnish).