Pat the 2 ahi tuna (yellowfin tuna) steaks dry with a paper towel. Place on a plate or inside a plastic bag.
Mix the 2 tablespoons soy sauce, 1 tablespoon toasted sesame oil, 1 tablespoon honey, ½ teaspoon kosher salt, ¼ teaspoon black pepper, and ¼ teaspoon cayenne pepper until honey is fully dissolved. Pour over the ahi tuna steaks and turn over to coat completely. Optional: allow to marinate for at least 10 minutes, or up to overnight in the refrigerator.
Heat a medium skillet (preferably non-stick or a well-seasoned cast iron skillet) on medium-high to high until very hot.
Add the 1 tablespoon oil to the hot pan. Sear the tuna for 1 - 1½ minutes on each side for medium rare (2 - 2½ minutes for medium-well to well, 30 seconds for very rare).
Remove to a cutting board. Slice into ½ inch slices and serve garnished with green onions, toasted sesame seeds, and lime wedges, if desired.
