Grilled Tuna Nicoise Platter

• 8 (1-inch-thick) fresh tuna steaks (about 4 pounds)
• Good olive oil
• Kosher salt
• Freshly ground black pepper
• 3/4 pound French string beans (haricots verts), stems removed and blanched
• 1 recipe French Potato Salad, recipe follows
• 2 pounds ripe tomatoes, cut into wedges (6 small tomatoes)
• 8 hard-cooked eggs, peeled and cut in 1/2
• 1/2 pound good black olives, pitted
• 1 bunch watercress or arrugula
• 1 can anchovies (optional)

For the vinaigrette:

• 3 tablespoons Champagne vinegar
• 1/2 teaspoon Dijon mustard
• 1/2 teaspoon kosher salt
• 1/4 teaspoon freshly ground black pepper
• 10 tablespoons good olive oil

French Potato Salad:

• 1 pound small white boiling potatoes
• 1 pound small red boiling potatoes
• 2 tablespoons good dry white wine
• 2 tablespoons chicken stock
• 3 tablespoons Champagne vinegar
• 1/2 teaspoon Dijon mustard
• 2 teaspoons kosher salt
• 3/4 teaspoon freshly ground black pepper
• 10 tablespoons good olive oil
• 1/4 cup minced scallions (white and green parts)
• 2 tablespoons minced fresh dill
• 2 tablespoons minced flat-leaf parsley
• 2 tablespoons julienned fresh basil leaves