Place rack in center of oven and preheat to 450 degrees.
Heat 3 teaspoons of olive oil in a medium pan over medium-low heat. Add onions, asparagus and salt.
Saute, stirring frequently, until onions start to brown, about 10 minutes.
Meanwhile, remove pizza from packaging. Spread remaining teaspoon of olive oil and the garlic over the pizza.
Cut the prosciutto slices crosswise into 1" wide strips. Place strips evenly over the pizza (it will not cover the pizza completely).
Distribute the onions and asparagus over the prosciutto, and sprinkle the cheese on top. Bake for 7-8 minutes, until edges turn golden. Cut into squares, serve and enjoy!