Mix all ingredients for the fish marinade in a medium bowl and coat fish with it, marinating for at least a 1/2 hour or preferably overnight.
Blanch potatoes and green beans. Cool, set aside.
Make Nicoise dressing. Mix all the ingredients together in a medium size bowl. Add cannellini beans, roasted peppers, capers, olives.
Grill fish over a grill or campfire using a grate, charring fish over hot coals for just a few minutes, with a metal spatula, move to cooler spot, or place on foil, or even a bed of lemon slices, until cooked to your desired done-ness.
Assemble the salad. Lay down a hearty bed of greens. Spoon a little Nicoise dressing from the bowl of marinated vegetables over the greens. Arrange or divide the marinated bean mix over the dressed greens, and arrange or divide the potatoes and green beans drizzling with a little marinade, and top with charred fish. Garnish with sliced cherry tomatoes and give fish a little squeeze of lemon, cracked pepper.