In a bowl, mix tamari, garlic, cilantro, green onions, and sesame oil. Add chicken thighs and coat evenly. Cover and marinate in the refrigerator for at least 1 hour.
Thinly slice cucumber, carrots, red onion, and bell pepper. In a separate bowl, combine the vinegar and a pinch of salt. Add the vegetables, toss to coat, and set aside to pickle while preparing the other ingredients.
In a small bowl, whisk together avocado mayo, sriracha, tamari, honey, and lime juice until smooth. Set aside.
In a shallow dish, combine gluten-free crumbs and salt. Remove chicken from the marinade, shaking off excess, and coat thoroughly in the crumb mixture.
Heat a skillet over medium heat with a few tablespoons of oil. Pan-sear the breaded chicken thighs for about 4-5 minutes per side, until golden brown and cooked through. Transfer to a plate lined with paper towels.
Toast the slices of gluten-free sourdough bread. Slice the avocados and have the chili crisp ready.
Spread sweet & spicy mayo on one side of each toasted bread slice. Layer the sandwich with avocado slices, chicken, pickled veggies, and a drizzle of chili crisp. Top with the second slice of bread. Slice the sandwich in half and serve immediately. Enjoy!