Heat the oil in a heavy large skillet over medium heat. Add the garlic
and saute until fragrant, about 30 seconds. Stir in the sage
and thyme. Add the tomatoes. Increase the heat to medium-high and simmer
for 2 minutes. Add the beans. Simmer until the tomatoes
are tender and the juices evaporate by half, about 5 minutes. Turn off heat and stir in the prosciutto, being careful not to overcook the prosciutto
. Season the beans, to taste, with salt and pepper.
Arrange the arugula or mixed baby greens over a platter. Spoon the beans over the greens and serve.