Place eggs in a large saucepan. Cover them with cool water by 1 inch. Slowly bring water to a boil over medium heat; when the water has reached a boil, cover and remove from heat; let sit 12 minutes. Transfer eggs to a colander and run under cool water to stop the cooking process. Peel, slice and set aside.
Cook fresh green beans in a large pot of boiling salted water, uncovered, for 4-5 minutes until crisp tender. Transfer immediately to an ice bath to stop the cooking process. Add potatoes to the boiling water and simmer uncovered for 15-20 minutes, until tender. Drain in a colander and set aside.
Rub tuna steaks with olive oil and season with salt and pepper. Heat a skillet over medium-high heat and sear tuna for two minutes on each side. Transfer to a cutting board and slice into strips.
Arrange all ingredients between four large plates or bowls (or you can make this on one large platter) and drizzle with balsamic vinegar and extra virgin olive oil. Season with sea salt and pepper and enjoy.
Nicoise olives can be used if you're able to find them
Boston Bibb lettuce will also work great!
For best results, use a good quality balsamic vineagar