How to Make It
Remove pizza dough from refrigerator, and let stand at room temperature 30 minutes.
Preheat oven to 500°F with an oven rack in center of oven. Meanwhile, cook sausage in a large nonstick skillet over medium-high until no longer pink, 6 to 8 minutes, breaking it into small pieces. Transfer to a plate lined with paper towels. Without wiping skillet, add 2 tablespoons of the oil to drippings in skillet. Add sliced onions and 1⁄2 teaspoon of the salt; cook over medium, stirring often, until onions are golden brown and tender, about 10 minutes. Remove from heat.
Combine kale, basil, Parmesan, garlic cloves, 2 tablespoons of the oil, and remaining 1⁄4 teaspoon salt in a food processor. Process until smooth, stopping to scrape down sides, about 30 seconds.
Heat a 12-inch cast-iron skillet over medium for 2 minutes. Add 1 tablespoon of the oil to skillet; swirl to coat. Sprinkle skillet with cornmeal. Stretch or roll dough into a 14-inch circle, and carefully place in hot skillet, pressing onto bottom and up sides. Increase heat to medium-high; cook until dough begins to bubble, 2 to 3 minutes. Working quickly, spread kale pesto over bottom of crust; top with sausage, onions, mozzarella, and feta. Sprinkle with crushed red pepper. Brush exposed crust edges with remaining 1 tablespoon oil. Place skillet in preheated oven on middle rack, and bake until cheeses are melted and crust is golden brown, 12 to 15 minutes.