In a small bowl, whisk together the vinegar, soy sauce, lime, ginger, mustard and cilantro. Pour in the oil and continue to whisk until emulsified.
Season the tuna fillets with salt and pepper; lightly coat with oil. Put sesame seeds on a plate. Coat top and bottom of each fillet with seeds. Heat a large, dry skillet over high heat. Add fillets; cook about 3 minutes. Turn; cook until desired doneness, about 3 to 4 minutes for rare. Slice the tuna into 1-inch thick strips.
Mix the greens together and spread out on a platter. Add the green onions, rice noodles almonds, and orange segments. Lay the tuna strips on top then drizzle with the vinaigrette. Season with salt and pepper and serve immediately.