Preheat the oven to 400° F. Line a rimmed baking sheet with foil, and place a cooling rack on top of the foil

Lay the bacon strips on the rack, and bake until desired crispness, 10-15 minutes

Prepare an ice bath by filling a large mixing bowl with ice cubes and water. Set aside

Bring a large pot of water to a boil. When the water comes to a boil, carefully drop the green beans into the water and boil for about 2-3 minutes. You want the beans to have a slight crunch and still be bright green

 If working in batches, remove the beans with a slotted spoon and transfer directly into the prepared ice bath. If not, simply drain the hot water and quickly transfer the beans to the ice bath

Drain the green beans from the ice bath once they are cooled, and set aside in a colander to dry

Heat a large skillet over medium-high heat and add the oil, and the onions. Cook until the onions begin to become translucent, 4-6 minutes

 Add the minced garlic and drained green beans, and cook for 2-3 minutes, moving the beans around frequently

In the last minute of cooking, add the vinegar, salt, black pepper, and bacon crumbles. Toss gently to combine