In a bowl, combine the gochujang, low-sodium soy sauce, water, brown sugar, sesame oil, and minced garlic and mix well. Set aside.
Cut chicken into bite-sized pieces and place in a bowl. Add 5 tablespoons of the gochujang mixture into the bowl of chicken and combine well. Set aside to marinate for 10 minutes.
Heat the canola oil on a large pan over medium heat. Add in the marinated chicken and cook for about 5 minutes, stir-frying the chicken pieces once in a while to cook each side of the chicken pieces. Increase the heat to high and add in the rest of the gochujang sauce mixture. Stir-fry for about 3-5 more minutes until the sauce is thicker and the chicken is cooked thoroughly. Remove from heat.
Serve in a serving bowl and top with roasted sesame seeds and green onions.