Season the tuna steaks with salt and pepper and place in a lidded container. In a small bowl, whisk 2 tablespoons olive oil with the fresh herbs and garlic. Brush the tuna steaks with the herb mixture, cover, and refrigerate for 2 to 4 hours.
Preheat the oven to 350°F.
On a baking sheet, season the potatoes with salt and pepper and drizzle with the remaining 1 tablespoon olive oil; toss to coat. Roast for about 18 minutes, until fork-tender.
Bring a large pot of salted water to a boil for the green beans. Prepare an ice bath by filling a large bowl with water and ice. When the water boils, add the green beans for 2 to 4 minutes then immediately put them into the ice bath to stop cooking. Take them out of the ice bath after 1 to 2 minutes.
Heat a grill pan or large skillet over high heat and lightly spray or brush with olive oil. Add the marinated tuna steaks and sear for about 2 minutes on each side.
Whisk or blend all of the dressing ingredients together and season to taste.
Divide the lettuce, roasted tomatoes, roasted potatoes, green beans, eggs, and olives between bowls and top each with a tuna steak. Drizzle with dressing and serve.