To prepare the tuna, whisk together the olive oil, garlic, lemon juice, lemon zest, oregano, cayenne pepper, garlic salt and pepper. Place the tuna in a baking dish and pour the marinade over the steaks, coating it evenly. Allow to marinate for 15 to 20 minutes. While the tuna is marinating, prepare the vinaigrette and vegetables.

For the vinaigrette, whisk together the shallot, vinegar and mustard in a medium-size bowl. Slowly pour in the oil while whisking rapidly to create a temporary emulsion. Whisk in the chives, and season with salt and pepper to taste.

Place the potatoes, green beans, tomatoes, olives and watercress in a large bowl, and dress with just enough of the dressing to coat. Set aside.

Heat a grill pan over medium-high heat. Grill the tuna on each side until caramelized, 1 to 2 minutes per side. Remove from the grill and set aside. The tuna should be rare to medium rare in the center. Allow the tuna to rest for 2 to 3 minutes, and then cut into slices.

To assemble the dish, spoon a small amount of the salad onto each plate. Top with slices of the grilled tuna and the hard-boiled eggs, and lightly drizzle with the vinaigrette.

Garnish with capers and anchovies, if desired.

• To blanch green beans, bring a large pot of water to a boil and add a generous pinch of salt. Drop the beans in the boiling water and cook until they are crisp yet tender, 2 to 4 minutes. Shock the beans in a bowl of ice water. Once cold, remove them from the bowl and drain well.

• To make perfect hard-boiled eggs, place your eggs in a saucepan and cover with cold water. Bring to a full boil, and then reduce the heat to a simmer. Cook uncovered for 9 minutes. Shock the eggs in an ice bath until cold. Peel the shells off the eggs, rinse, and enjoy!