Add the olive oil to a large skillet and heat over high heat. Season the tuna steaks with salt and pepper.
Place the sesame seeds on a shallow plate. Place the tuna steaks on in the sesame seeds, one at a time, and coat both sides. Press the seeds onto the tuna so they stick well.
Once the pan is hot, place the tuna steaks in the pan and sear for 2 minutes. You want to see the bottom of the steak cooked barely. If you prefer your tuna to be more cooked, leave it on for 1-2 minutes more. Gently flip the tuna steaks over and sear for another 2 minutes. Remove the tuna from the pan and slice it into thin strips.
Assemble the tacos by adding two tuna strips, red cabbage (or fish taco slaw), and diced mango. Top the tacos with chopped fresh cilantro, baja sauce and serve with lime wedges!
Notes
● When slicing the cooked tuna, use a sharp knife to cut thin, even slices against the grain. This ensures a more enjoyable texture and bites in your tacos.