Heat the grill to high. Combine the first six ingredients in a medium saucepan. Bring to a boil, then reduce heat and simmer for 4-5 minutes.
Meanwhile, place the baguette slices on a baking sheet and grill until toasted on one side. Turn over, sprinkle with cheese and grill for another 1-2 minutes until the cheese is melted and golden. Season the beans to taste and serve over the cheesy toast.