Pull the leafy greens off the tough stalks of the mustard greens. Discard of the stalks and set greens aside.
In a sauté pan over medium heat, add the olive oil, garlic and red pepper flakes. Once the garlic beings to shimmer and shake in the pan, add the greens and juice from lemon. Quickly toss all of the ingredients together and sauté for 2 minutes. Take the pan off the heat, season to taste with salt and pepper and set aside.
Preheat oven with pizza stone to 500 degrees
On a sheet of foil dusted with flour, place pizza dough in the middle and gently roll the pizza dough into a circle until thin (you can also pick up the dough and gently stretch the dough with your hands.) Spoon 2 tablespoons of marinara over the dough and spread close to the edges.
Place in preheated oven for 12-15 minutes, or until golden and crispy. Transfer the pizza to a plate and scatter with prepared mustard greens and a healthy scattering of Parmesan cheese shavings. Enjoy!