Wash your tuna steak under cold water, then dry it thoroughly with paper towels. Set aside.
Mix together sesame seeds and pepper. Salt both sides of your steak, then dip into the sesame seeds—nestle the steak into the seasoning, making sure all sides are covered, including the outside edges.
Heat the sesame oil in a nonstick pan. When oil is hot, lay the steak in and sear for 2 minutes on each side. Use tongs to sear the edges of the steak, too (but only for 30 seconds). Allow to cool slightly, then, cutting against the grain, slice tuna into 1/2 inch thick strips.
To assemble, spread the spinach on a platter or in large bowl and top with the ahi, green beans, corn, olives, radishes, mozzarella cheese, tomatoes, basil, and almonds. Serve cold and enjoy!