Mix mayo, yuzu juice, and yuzu kosho in a bowl to combine. Transfer to a squeeze bottle until ready to serve.
Peel and thinly slice the Japanese sweet potato, about ¼ inch thick.
In a stainless steel or cast iron pan, heat the ghee or avocado oil over medium-high heat until it starts to smoke or ripples. Place the Japanese sweet potato slices in a single layer, taking care not to overcrowd the pan. Cook for 1-2 minutes on each side being careful not to burn. Remove, sprinkle with salt, and set aside.
Season the tuna with salt and pepper. Coat tuna in yuzu furikake, coating evenly.
In a stainless steel or cast iron pan, heat the ghee or avocado oil over medium-high heat until it starts to smoke or ripples. Place the tuna in the pan and cook for about a minute. The white sesame seeds start to turn golden brown.
Carefully turn the tuna over and cook for about another minute, checking after 45 seconds. Transfer the tuna to a cutting board and cut into 1/4 inch thick slices.
Arrange potato crisps in a single layer and place a piece of tuna on each potato crisps. Using a squeeze bottle, drizzle yuzu mayo over each tuna topped potato crisp. Transfer to a serving platter and garnish with fresh parsley, cilantro, or micro green. Serve immediately.