Bring a large pot of well-salted water to a boil. Cook the beans in the water until crisp-tender, 4 to 6 minutes. Drain and run under cold water to cool. Drain well.
Position a rack in the center of the oven and heat the oven to 425°F. Put the beans in a medium bowl, toss with 1 Tbs. of the olive oil, and season with 1/4 tsp. salt and a few grinds of pepper. Spread the beans in one layer on a heavy-duty rimmed baking sheet, leaving space for the tomatoes.
In a small bowl, toss the tomatoes with the remaining 1 Tbs. oil, garlic, thyme, 1/4 tsp. salt, and a few grinds of pepper. Spread the tomatoes on the baking sheet.
Roast the beans and tomatoes just until the tomatoes start to split, 7 to 10 minutes. Slide the beans onto a serving dish, top with the tomatoes, and dot liberally with the tapenade. Serve, with additional tapenade on the side.