Bring a large pot of water to a boil. Add green beans and 1 tsp salt. Cook until tender, 6 to 7 minutes. Drain. Heat oil in a large skillet on medium. Add beans, thyme, garlic, half of the orange zest, 1/2 tsp salt, and 1/4 tsp pepper. Cook, stirring frequently, until garlic is just lightly golden, 2 to 3 minutes. Stir in juice; cook until mostly evaporated, 30 seconds to 1 minute more. Garnish with remaining zest.