Cook up some rice if you haven’t already (instructions here). To a large skillet over medium-high heat, warm 1 tablespoon oil. Add the chicken, spread it out into one layer (like a giant patty), sprinkle with salt and cook for 3-5 minutes, undisturbed, or until the chicken is browned. Flip and break up into bite-sized chunks and continue to cook until cooked through and all the water has evaporated, about 1-2 more minutes. Transfer to a plate or bowl.
While the chicken cooks, in a small jar, bowl, or liquid measuring cup, mix together the soy sauce, ¼ cup water, sugar, vinegar, and garlic.
To the skillet over medium-high heat, add the remaining 1 tablespoon oil, broccoli, edamame, and white/light green parts of the scallions. Cook for a minute or two, stirring often, then pour the soy sauce liquid into the skillet and scrape up anything stuck to the bottom of the pan. Return the chicken to the skillet and simmer for 2 minutes or until the broccoli is fork tender, stirring occasionally.
Meanwhile, in the same jar or bowl you whisked the sauce, add the tapioca starch and remaining 2 tablespoons water and mix together to make a slurry. Pour into the skillet and simmer for 1-2 more minutes or until thickened and coating everything nicely, stirring constantly.
Serve over warm rice topped with the green scallions, sesame seeds, and sriracha or chili oil (if using).