Trim the ends from the green beans. Cover a baking sheet with foil. Preheat oven to 425 degrees.
Heat balsamic vinegar, sugar and pinch of salt over medium heat stirring constantly until sugar is dissolved. Bring to a boil, then reduce to low. Simmer until sauce is reduced by half and thickened; about 15 minutes.
Meanwhile, arrange green beans on the cookie sheet. Drizzle with olive oil and stir to coat. Sprinkle with salt and pepper.
Roast beans in the preheated oven for 8-12 minutes, depending on desired doneness (8 minutes for a crisp-tender, 12 minutes for soft).
Place green beans in a serving dish and drizzle with balsamic glaze. Serve immediately.