In a large ziplock bag, combine chicken pieces, salt, and pepper. Shake to coat evenly.
Heat olive oil in a skillet over medium-high heat. Sear chicken for 5-7 minutes until golden brown.
Transfer the browned chicken into your slow cooker.
In a bowl, whisk together soy sauce, water, honey, hoisin sauce, garlic, ginger, and red pepper flakes. Pour over chicken.
Cover and cook on LOW for 2-4 hours or on HIGH for 1-3 hours. Check for doneness earlier if your slow cooker runs hot.
Thirty minutes before serving, whisk together cornstarch and water in a small bowl. Stir this slurry into the slow cooker.
Add red bell pepper, zucchini, cashews, and dried chili peppers. Cook on HIGH for another 20-30 minutes until veggies are tender and sauce has thickened.
Garnish with sesame seeds and chopped green onions. Serve over rice, quinoa, or noodles.