Season chicken with salt and pepper then place in a large skillet with oil, over medium-high heat, cook chicken until lightly browned, about 5-6 minutes.
Add chicken to a slow cooker.
Whisk together soy sauce, water, hoisin sauce, honey, minced garlic, sesame oil, grated ginger, and red pepper flakes in a small bowl and pour into the slow cooker.
Place the lid on the slow cooker and cook on LOW for 3-4 hours.
Around the last 30 minutes of cook time, whisk together the slurry and add to the slow cooker, along with dried red chili peppers, red bell peppers, zucchini, and roasted cashews.
Place the lid back on the slow cooker and cook on HIGH for the remaining 30 minutes.