In a medium bowl, combine bite-sized chicken breast pieces with low sodium soy sauce, sea salt, and cornstarch, and let marinate for at least 10 minutes.

Heat a large skillet or wok over medium-high heat and add canola oil. Once hot, add the marinated chicken in a single layer and cook for 5-7 minutes until golden brown and cooked through.

Add chopped red bell pepper, minced ginger, and garlic, stir-frying for 2-3 minutes until fragrant and vegetables are tender-crisp.

If using, mix in sliced water chestnuts. Pour in hoisin sauce, toasted sesame oil, rice vinegar, and brown sugar, stirring to combine and let bubble for a minute or two.

Prepare a slurry by mixing cornstarch with water and add it to the skillet, stirring as it cooks for an additional 2 minutes to thicken the sauce.

Remove from heat, garnish with sliced green onions, and serve immediately over warm rice or stir-fried vegetables.