Heat 1/2 tablespoon olive oil in a pan over medium-low heat. Add onion and a sprinkle of salt; saute until translucent, 3 to 5 minutes. Add green beans, tomatoes with their juices, chicken broth, and garlic. Increase heat to medium-high and simmer until only 2 to 3 tablespoons of liquid remain, up to 15 minutes. Drizzle remaining olive oil over the top.
