6 tablespoons fresh orange juice, plus more to taste
1/4 cup white-wine vinegar or red-wine vinegar
1 tablespoon Dijon mustard
1 1/2 pounds red potatoes (5-6 medium), scrubbed and halved
1 1/4 pounds green beans, trimmed
Juice of 1 large lemon
2 tablespoons extra-virgin olive oil
1/2 teaspoon salt, divided
1 pound Pacific halibut or striped bass (see Note)
1/4 teaspoon coarsely ground pepper, plus more to taste
1 large head Boston lettuce
1 1/2 cups grape tomatoes
3 hard-boiled eggs (see Tip), peeled and cut into wedges
1/4 cup sliced pitted black Niçoise or Kalamata olives
1/4 cup finely chopped fresh parsley
To prepare vinaigrette: Peel the garlic and smash with the side of a chef’s knife. Using a fork, mash the garlic with 1/4 teaspoon salt in a small bowl to form a coarse paste. Whisk in 5 tablespoons oil. Add 6 tablespoons orange juice, vinegar and mustard; whisk until well blended. Taste and whisk in up to 4 tablespoons more juice to mellow the flavor; season with more salt, if desired. Set aside at room temperature.
To prepare salad: Bring 1 inch of water to a boil in a large saucepan fitted with a steamer basket. Add potatoes; cook until tender, 10 to 15 minutes. Remove to a cutting board. When cool enough to handle, slice and place in a shallow bowl. Drizzle with 1/3 cup vinaigrette; set aside.
Add beans to the steamer basket; cook until bright green and just tender, 4 to 6 minutes. Rinse in a colander with cold water until cool. Drain well. Place in a medium bowl and toss with 2 tablespoons vinaigrette.
Combine lemon juice, 2 tablespoons oil and 1/4 teaspoon salt in a sturdy sealable plastic bag; shake until the salt dissolves. Add fish and marinate for up to 20 minutes while you ready the grill.
Preheat grill to medium-high for 10 minutes, then reduce heat to medium. (For a charcoal grill, wait until the flames subside and only coals and some ash remain—flames will cause the oil on the fish to burn.)
Drain the fish and pat dry with paper towels. Season with the remaining 1/4 teaspoon salt and 1/4 teaspoon pepper. Oil the grill rack (see Tip). Grill the fish, turning once, until browned and just cooked through, 4 to 5 minutes per side for halibut; 3 to 4 minutes per side for bass.
Arrange lettuce leaves on a large serving platter. Arrange the fish (whole or flaked into large chunks), potatoes, green beans and tomatoes on top. Drizzle with the remaining vinaigrette. Garnish with eggs, olives, parsley and pepper to taste.