Remove the stems and center ribs from the collard greens and discard. Cut the leaves into 1/2-inch strips. Place the greens into a large, microwave-safe bowl with the water and cover tightly. Microwave on high for 5 minutes.

In the meantime, preheat a large skillet and cook the bacon for 2 minutes on each side. Remove the bacon from the pan, chop, and set aside. Add the oil and onion to the pan and cook until onions have softened, about 2 minutes. Add the collard greens and stir in the vinegar, maple syrup, red pepper flakes, and broth. Bring to a simmer and cook, covered, for 30 minutes. Add the chopped bacon to the pan, and season with salt.