Lightly season the tuna on both sides with Essence, salt and pepper.
In a large skillet, heat the oil over high heat. Add the tuna and cook on both sides until seared and medium inside, 3 to 4 minutes per side. (Alternatively, grill the tuna until medium.) Place on a plate, let cool, then refrigerate until chilled, 2 to 4 hours.
Bring 2 medium pots of salted water to a boil. Add the potatoes to 1 pot and blanch until just tender, 3 to 4 minutes. Drain in a colander and shock in an ice bath. Drain well and refrigerate until ready to serve.
Add the green beans to the other pot and blanch until tender, about 4 minutes. Drain in a colander and shock in an ice bath. Drain well and refrigerate until ready to serve.
In a 3-quart clear glass bowl, arrange the lettuce across the bottom. Top with the chilled potatoes and green beans, then the tomatoes, eggs, and olives. With a fork or your fingers, break the tuna into large bite-sized chunks and arrange over the top of the olives. Drizzle the dressing over the top, garnish with capers and fresh herbs, and serve.
Yield: 6 to 8 servings