Preheat the oven to 400 degrees. Place the chopped potatoes on a large baking sheet, then toss with one tbsp of olive oil and a pinch of salt and pepper until all of the potatoes are coated. Roast the potatoes for about 30 minutes, until they are lightly golden and slightly crispy.
While the potatoes are cooking, place the green beans on another large baking sheet. Toss with one tbsp of olive oil, the garlic cloves, and a pinch of salt and pepper until all of the green beans are coated. Roast for about 20 minutes, until just starting to turn brown and slightly soft.
Once the potatoes and green beans are roasted, transfer them to a large serving bowl.
Mix together the vinaigrette: Combine all of the vinaigrette ingredients in a jar with a tight fitting lid, and shake it to combine. Then pour the vinaigrette onto the potatoes and green beans. Toss to combine, making sure everything is evenly coated.
You can eat this salad, warm, at room temperature, or cold.