Preheat a cast-iron skillet over medium-high heat.
Sprinkle the steak with pepper and 1 teaspoon salt. Add the oil to the skillet, then the steak, and cook to medium or until the internal temperature is 135 to 140 degrees F on an instant-read thermometer, about 5 minutes per side. Transfer the steak to a cutting board and let rest for about 7 minutes.
Meanwhile, add the panko, sesame seeds and remaining 1/4 teaspoon salt to a small skillet over medium heat. Cook, stirring frequently, until the panko is golden brown. Transfer to a bowl and set aside to cool. Slice the steak into thin strips.
Add mayonnaise and sriracha to a medium squeeze bottle and shake until combined (see Cook's Note).
Place a soy wrapper on a clean workspace in front of you. On the edge of the wrapper closest to you, squeeze a line of spicy mayo. Lay down 2 avocado slices, lengthwise, touching each other. Stack a few pepper slices so that the entire edge is covered in a layer of peppers. Squeeze a line of the spicy mayonnaise on the peppers, then sprinkle about 2 tablespoons of the panko mixture over them. Add a few slices of steak on top of the panko. Carefully roll the whole mixture away from you, creating a thin tube. Add another thin line of mayonnaise to the outer edge of the wrapper to help you seal the roll. Set the tube aside and repeat with the remaining wrappers and ingredients.
Cut each into about 1 1/2-inch slices or rolls. Place the rolls on a serving plate.
If you don't have a squeeze bottle, you can mix in a bowl, then transfer to a resealable bag or a piping bag.