Season ahi tuna with salt and pepper. Sprinkle sesame seed evenly on both sides of tun. Pat into flesh.
Heat a small sauté pan to a medium-high heat. Once the pan is hot, add 1 tsp. sesame oil and olive oil. When the oil is hot, add tuna. Sear for 45 seconds, then flip and sear on the other side for another 45 seconds. Transfer to a plate and let cool.
In a small bowl, whisk together remaining sesame oil, mayo, soy sauce, and sriracha. Set aside.
Slice tuna into ¼-inch pieces.
Spread a little bit of the mayo on both tortillas. Add the rest of the mayo to a plastic baggie. Cut off the tip and set aside. Sprinkle the lettuce evenly between tortillas. Lay half of carrots down the middle of each tortilla, followed by cabbage. Evenly divide the tuna between tortillas. Sprinkle wontons on top of tuna. Use the plastic baggie to drizzle remaining mayo over tuna.
Wrap tortillas up, burrito-style. Cut in half. Serve.