Squash and Ricotta Pizza

Name: Squash and Ricotta Pizza
Ingredients: 2 tablespoons olive oil, plus more for brushing the squash; 1/2 large onion, thinly sliced; Kosher salt; 1/2 teaspoon ground sage; 1 pound pizza dough, homemade or store-bought; 1/2 cup whole-milk ricotta cheese; 1/2 cup shaved or grated Parmesan, plus more for serving; Freshly ground black pepper; 3 ounces butternut squash, peeled and shaved with a vegetable peeler into long strands; 1 cup loosely packed arugula; 1 teaspoon lemon juice; Crushed red pepper, for serving