To make the salad, parboil the potatoes in boiling water for 5 minutes. Do not overcook because you want them to be firm within the salad mixture. Slice the fennel bulb in half lengthwise and using a hand-held mandolin, slice the fennel into thin strips across the length of the bulb. If using a knife, just cut the fennel into the thinnest possible strips you can. Core the tomato and cut into thin strips. If the strips are too long you can cut them down a bit. You want the fennel strips and the tomato strips to be similar in scale or length.
Combine the potatoes, fennel, tomatoes, three-quarters of the microgreens and the shoots or sprouts into a large mixing bowl and mix nicely. Strip the leaves from the dill sprigs and combine with the salad gently.
In a small bowl, mix the olive oil and the lemon juice to make the dressing. Season with salt and pepper. Dress the salad lightly with the dressing being careful not to overdress the salad at first. You can always add a little bit of dressing is you like it a bit more moist.
In a large non-stick skillet over high heat, add the grapeseed oil until it comes to a shimmering state. Swirl the pan around a bit to coat the pan. Salt each fillet with the sea salt on all sides. Add the fish fillets to the pan away from you to prevent splashing onto you and, using a fish spatula, or other wide metal spatula, hold down each of the fillets with the spatula as they go in to allow the skin to be in full contact with the pan surface and to prevent the skin from curling up. Do this through the first minute or so with each fillet as you get them all in the pan. Reduce the heat to medium-low and cook undisturbed for 5 minutes total until you see the fish starting to become opaque around the edges. Tilt the pan and baste the fish with the oil and juices that have accumulated in the pan for about 30 seconds. At this point, the fish should be able to release nicely from the pan. Flip each fillet very carefully using your spatula and the tip of your finger to hold the top of the fish as you flip it. Cook on the flesh side for just 30 seconds and remove from the pan. Squeeze fresh lemon juice over each fillet.
To present, place a generous portion of the salad on one side of each plate. Gently tilt each bass fillet against the salad mixture and garnish with the rest of the micro greens, reserved fennel fronds and an extra squeeze of lemon juice. Sprinkle with the flake salt to finish.