Wash and pat dry the green beans.
Trim both the ends. Cut into halves if long in size.
In a large cast iron skillet or any heavy bottom pan, heat a little oil till smoking hot. Then reduce to medium heat.
Add the green beans to the hot oil and leave it for 2 - 3 minutes untouched.
Then give a nice stir making sure all beans are equally cooked. Allow them 3 - 4 minutes each time to get nicely charred and blistered.
Once done remove from pan and keep aside.
To the same pan add a little oil (if required).
Add minced garlic and saute till starts to change color.
Add soy sauce and vinegar. And hot sauce for spicy ones or skip it if don't need it.
Next, add the beans and toss them well.
Season with black pepper and salt if required since soy sauce already contains some salt in it.
Stir-fry for 1 - 2 minutes to infuse the flavors well. Remove once done and serve.