Roughly chop the king oyster mushroom stems. In a food processor, pulse the chopped mushrooms until they have a flaky, 'shredded' texture similar to cooked shrimp. Be careful not to over-process into a paste. Transfer to a large mixing bowl.

Add the rinsed and drained chickpeas to the food processor and pulse a few times until roughly mashed but still chunky. Add the pulsed chickpeas to the bowl with the mushrooms.

To the bowl, add the all-purpose flour, panko breadcrumbs, vegan mayonnaise, fresh lemon juice, Old Bay seasoning, smoked paprika, onion powder, garlic powder, crumbled nori, and sriracha (if using). Mix well with your hands or a spoon until all ingredients are thoroughly combined and sticky enough to form patties. Season with salt and black pepper to taste.

Divide the mixture into 4 equal portions and shape each into a firm, approximately 3/4-inch thick burger patty. Place the patties on a plate or baking sheet lined with parchment paper. For best results, chill the patties in the refrigerator for at least 15-20 minutes to help them firm up.

Heat 2 tablespoons of olive oil in a large skillet over medium heat. Once hot, carefully place the patties in the skillet. Cook for 4-6 minutes per side, or until golden brown and crispy.

Preheat air fryer to 375°F (190°C). Lightly spray each patty with cooking oil. Place patties in a single layer in the air fryer basket (you may need to cook in batches). Air fry for 10-12 minutes, flipping halfway through, until golden brown and cooked through.

Lightly toast the vegan burger buns if desired. Assemble the burgers with lettuce, sliced tomato, red onion, and a generous dollop of vegan tartar sauce or remoulade. Serve immediately.