Cook all veggies except garlic and kale in olive oil until amost done
Add garlic and kale at the end, let the kale wilt completely
In a small bowl, whisk together soy sauce, rice vinegar, sesame oil, salt, pepper, and red pepper flakes if using.
Pour the sauce over the vegetables in the skillet. Stir well to coat all the vegetables.
Cook for another 2-3 minutes, allowing the flavors to meld together.
Serve the stir-fry hot over cooked rice