In a small bowl, whisk together the tamari, maple syrup, rice vinegar, garlic, ginger, tahini, tomato paste, chili garlic sauce, cornstarch, water, and red pepper flakes. Set aside.
Heat the avocado oil in a large skillet over medium-high heat. Add the chicken and cook for 6–8 minutes, stirring occasionally, until lightly browned and cooked through. The internal temperature should reach 165°F. Transfer the chicken to a plate.
Add the frozen vegetables to the same skillet. Cook for 5–7 minutes, stirring occasionally, until heated through and tender-crisp.
Add the chickpeas and cooked chicken to the skillet. Pour the sauce over everything and stir well.
Cook for another 2–3 minutes, stirring frequently, until the sauce thickens and evenly coats the chicken and vegetables.
Divide among three bowls and garnish with sesame seeds and sliced green onions, if desired.