Pat tuna dry with a paper towel.
Coat surface of tuna with eggs.
In a large bowl, mix the next 4 ingredients (salt and pepper through thyme). Coat the surface of the tuna with the pistachio mixture.
In a large skillet over high heat, heat the coconut oil. To the skillet, add the tuna and cook for 3 minutes on each side, until the outside has a crispy crust. Continue to cook until tuna is to desired level of doneness. Serve warm.