Heat 1 tbsp olive oil in a large heavy skillet over medium-high heat. Add mushrooms and sauté until tender, about 5 minutes, stirring constantly. Stir in vegetable broth, wine, tomato, and thyme; bring to a boil. Reduce heat to medium-high; cook, uncovered, 15 minutes, stirring frequently.

Meanwhile, combine water, beans, chives, contents of Spice Sack, and remaining tbsp olive oil in a medium saucepan. Bring to a boil; stir in couscous. Cover; remove from heat, and let stand 5 minutes.

Fluff couscous lightly with a fork, and spoon into shallow dinner bowls. Top with mushroom sauce.