Bring a medium pot filled halfway with water to a boil. Once boiling, add in the green beans and cook for 5 minutes or until tender. Drain into a colander and place in a large mixing bowl along with the tomatoes, olives, and onions. Set aside.
Meanwhile, place the eggs in a medium saucepan and cover with water and a pinch of salt. Cover and bring to a roaring boil. Once boiling, turn off the heat and let stand for 12-14 minutes to hard boil. When done, rinse under cold water until able to be handled. Peel the eggs and halve. Set aside.
While eggs and green beans cook, whisk all ingredients for the vinaigrette together and set aside.
In a large skillet, place in the olive oil. Once oil heats, add in the potato noodles, season with salt, pepper and garlic powder. Cover and cook for 5-7 minutes or until cooked all the way through, uncovering occasionally to toss.
Once potatoes are cooked, add to the bowl with the green beans and veggies and pour in the vinaigrette. Set aside.
Season both sides of the tuna steak with salt and pepper, pressing the pepper into the tuna. Pour the lemon juice over the tuna. Wipe down the large skillet and place it back over medium heat. Once heated, add in the seasoned tuna and sear for 1-2 minutes, flip over and sear another 1-2 minutes. If you prefer your tuna well done and not rare, cook for 3-4 minutes per side or until done to your preference.
Divide the potato noodle mixture into bowls and top each bowl with 1/3 of the tuna and 1 hard boiled egg. Garnish with freshly cracked black pepper and enjoy immediately.