• 1/3 cup black sesame seeds
• 1/3 cup sesame seeds 
• 4 tuna steaks, about 6 ounces each 
• 2 tablespoons peanut oil 
• 4 teaspoons rice wine vinegar 
• 2 tablespoons extra-virgin olive oil 
• 1/2 teaspoon sesame oil 
• 1/2 teaspoon low-sodium soy sauce 
• 1/2 teaspoon sugar 
• 4 cups mesclun greens 

On a large sheet of wax paper, combine the sesame seeds. Coat each tuna steak with the seeds, pressing the seeds into the fish with the heel of your hand. In a large skillet over medium-high heat, heat the peanut oil for 2 minutes. Add the tuna and cook for 3 to 5 minutes per side, depending on how well done you like your fish. Transfer the tuna to a cutting board to rest. 

In a small bowl, whisk together the rice wine vinegar, olive oil, sesame oil, soy sauce and sugar. Set aside. 

Place the mesclun greens in a large bowl; add the dressing and toss to coat. Arrange the dressed greens in the middle of individual plates. Slice the tuna diagonally and fan out the slices on top of the greens. Serve immediately. 

Black sesame seeds are available at Whole Foods and Asian specialty markets