In a small bowl, whisk together the low-sodium soy sauce, rice vinegar, 1 teaspoon minced ginger, and 1 clove minced garlic. In a separate bowl, mix the chicken broth with cornstarch until smooth. Set both mixtures aside.
Toss the sliced chicken with 1 tablespoon of the soy sauce mixture. Let it sit for at least 5 minutes while you prep the vegetables.
Heat 1 tablespoon olive oil in a large wok or non-stick skillet over medium-high heat. Add the marinated chicken pieces in a single layer and cook for 3-4 minutes until golden brown and cooked through. Remove chicken from the pan and set aside.
Add the remaining tablespoon of olive oil to the same pan. Add the remaining ginger and garlic, stir for 30 seconds until fragrant. Add onions and cook for 1 minute, then add carrots and broccoli. Stir-fry for 2 minutes. Add bell peppers and snow peas, continuing to stir-fry for another 2 minutes or until vegetables are crisp-tender.
Return the chicken to the pan. Pour in the remaining sauce mixture and the cornstarch-broth mixture. Stir constantly until the sauce thickens, about 1-2 minutes. Drizzle with sesame oil, toss to combine, and remove from heat.
Transfer to a serving dish, sprinkle with sesame seeds and fresh cilantro if desired. Serve immediately for optimal flavor and texture.