Preheat oven to 425 degrees. Brush olive oil over pizza crust and sprinkle with garlic salt and rosemary. Crumble feta cheese over top and bake for about 8 minutes or until the cheese is golden brown.
While pizza is baking, caramelize the onions by steeping them in 1 tablespoon of water in a covered skillet. Cook at medium high heat until the onions are tender and transluscent. Remove from heat. Toss the pears with the onions and keep covered until ready to top the pizza.
Top the pizza with chopped walnuts, pears and onions, and fresh arugula.