Heat a large skillet (preferably cast iron) over medium-high heat.
Add olive oil to skillet and when hot, add green beans. Let green beans sit in skillet (without stirring) for about 2 minutes, until they're starting to blister.
Gently toss and let sit for another 2 minutes to continue to blister. Repeat once more.
Add garlic to skillet, toss to combine, and cook for 1 more minute.
Remove from heat and toss green beans with soy sauce, black pepper, and red pepper flakes. If not using soy sauce, you can add salt here, too.