Crush sage leaves, garlic and pepper in a mortar and pestle to make a paste. If you do not have a mortar and pestle just chop them all together very finely. In medium bowl whisk together the herb paste with the juice from the lemon and olive oil. Add duck breast and marinate at least 2 hours.
Grill the duck breast over medium high heat, turning once, until it reaches an internal temperature of 130 degrees. Remove from grill and cover with an aluminum foil tent for 5 minutes.
Heat the grill to 400 degrees.
While the duck is cooking and resting, put the pizza crust on a pizza pan and top with cheese and chopped sage.
Slice the duck breast thinly and add to the pizza.
Create some indirect heat on your grill: - If you have 4 burners on your grill, turn off the middle two. - If your grill only has two burners place two metal bread pans (or bricks covered in foil) on the grill to raise the pizza away from direct flame. - If you are using charcoal, push the coals to the sides.
Grill the pizza until the cheese melts and the crust is cooked. For extra sage flavor, put the additional sage stems on the grill grate around the pizza. It will smoke and burn up.
Slice and serve the pizza.
Notes
For an easy homemade pizza crust use half of this recipe (save the other half in the fridge or freezer for another use).