Combine all the ingredients on a plate. Sprinkle the seasoning over tuna, pressing gently over sides.
Preheat a cast iron skillet over medium high heat. Add oil then sear the tuna steaks on both sides for 1 minute each side. The middle should be slightly pink.
On a small bowl, combine soy sauce, fish sauce and juice of 1 lime. Drizzle on tuna and serve.
Recipe by The Gluten Free at https://www.theglutenfree.com/lime-and-thyme-tuna-gluten-free/