1. Prepare the wonton crisps: Preheat your oven to 350°F (175°C). Line a large baking sheet with parchment paper. Brush both sides of each wonton wrapper lightly with oil, or spray with cooking spray. Arrange them in a single layer on the baking sheet without overlapping. Sprinkle lightly with sea salt. Bake for 8-10 minutes, flipping halfway through, until golden brown and crispy. Watch carefully in the last few minutes as they can burn quickly. Remove and let cool on the pan – they’ll continue to crisp as they cool.
2. Make the spicy mayo: In a small bowl, whisk together mayonnaise, sriracha, lime juice, and a pinch of salt. Start with 2 tablespoons of sriracha and add more if you want extra heat. Taste and adjust seasoning. Transfer to a squeeze bottle or small ziplock bag for easy drizzling. Refrigerate until ready to use.
3. Prepare the sweet soy glaze: In a small saucepan over medium heat, combine soy sauce, honey, rice vinegar, and sesame oil. Bring to a gentle simmer, stirring until honey dissolves completely. In a tiny bowl, mix cornstarch with water to create a slurry. Slowly whisk the slurry into the simmering sauce and cook for 1-2 minutes until it thickens to a syrupy consistency that coats the back of a spoon. Remove from heat and let cool. Transfer to a squeeze bottle for drizzling.
4. Marinate the tuna: Pat the tuna steak completely dry with paper towels – this is crucial for a good sear. In a shallow dish, combine 2 tablespoons soy sauce, sesame oil, grated ginger, and minced garlic. Add the tuna and turn to coat all sides. Let marinate for 10-15 minutes at room temperature while you prepare other components. Don’t marinate longer than 30 minutes or the acid will start to “cook” the fish.
5. Coat the tuna with sesame seeds: Remove tuna from marinade and pat dry again. Season both sides lightly with salt and pepper. Pour sesame seeds onto a plate and press each side of the tuna firmly into the seeds to create an even coating on all sides.
6. Sear the tuna: Heat a cast iron skillet or heavy pan over high heat until it’s smoking hot – this is key to a good sear. Add 1 tablespoon neutral oil and swirl to coat. Carefully place the sesame-crusted tuna in the hot pan. Sear for 60-90 seconds per side without moving it. You want a golden crust on the outside while keeping the center raw to medium-rare. The sides should show about ¼-inch of cooked (gray) tuna around a red raw center. Use tongs to sear the edges briefly, about 15-30 seconds each.
7. Rest and slice the tuna: Transfer the seared tuna to a cutting board and let rest for 2-3 minutes. Using a very sharp knife, slice the tuna against the grain into ¼-inch thick slices. Wipe your knife clean between cuts for the cleanest slices.
8. Assemble the wonton crisps: Arrange your crispy wontons on a serving platter. Place a thin slice of avocado on each wonton crisp. Top with a slice of the seared ahi tuna, folding or arranging it artfully on the avocado.
9. Garnish and serve: Drizzle each wonton crisp with spicy mayo in a zigzag pattern, then drizzle with the sweet soy glaze. Sprinkle with sliced green onions and extra sesame seeds. Add microgreens or cilantro if using. Serve immediately while the wontons are still crispy, with any extra sauces on the side for dipping.

Notes

• Tuna quality is paramount – Only use sushi-grade or sashimi-grade tuna from a reputable source. If you’re unsure about raw fish safety, you can sear the tuna longer to medium, though traditionalists prefer it rare.
• Don’t oversear the tuna – The goal is rare to medium-rare. The entire searing process should take less than 4 minutes total for a 1-inch thick steak.
• Make wontons ahead – Baked wonton crisps can be made up to 2 days ahead and stored in an airtight container at room temperature.
• Slice tuna just before serving – Pre-sliced tuna will oxidize and lose its vibrant color.
• Knife sharpness matters – A sharp knife is essential for clean tuna slices. A dull knife will tear the delicate fish.
• Temperature control – Let the tuna come to room temperature for about 15 minutes before searing for the most even cooking.