Start by making the dressing. Place all ingredients in a small food processor and blend until smooth. Adjust consistency by adding 1-2 Tablespoons water. Set aside.
To prepare the tuna steaks. Season on both sides with olive oil and the sesame seeds.
Preheat a grill pan over medium high heat and sear the tuna steaks for 3 mins per side until slightly charred with grill marks. The tuna should still be raw on the inside.
Let the tuna steaks rest for 5 minutes while you assemble the salad.
In a large plate, arrange the salad ingredients. Add more or less of your favorite ingredients to the salad.
Slice the tuna steak into strips and arrange them over the salad.
Drizzle the salad dressing over the salad and serve right away.
Enjoy.