Heat the 2 Tbsp. oil in a medium pot set over medium heat. Add the onion, carrot and celery and cook until softened, about 5 minutes. Add the tomato paste, cumin and chili flakes and cook 1 minute more. Add the chickpeas, stock and potato. Bring soup to a gentle simmer and cook 20 minutes, or until vegetables are quite tender. Puree the soup in a food processor or blender, or in the pot with an immersion blender. Return soup to a simmer; season with salt and pepper. Cover soup and reserve on low heat until scallops are ready.
Season the scallops with salt and pepper. Place the 1 Tbsp. oil in a pan and set over medium-high. Add the scallops and sear 1 to 2 minutes on either side, or until just cooked through.
To serve, ladle soup into shallow bowls. Set a 2 tsp. amount of pesto, and 2 scallops, in the centre of each soup bowl and serve.