Cook pasta according to package directions. Meanwhile, cook sausage in a large skillet over medium heat until browned, about 5 minutes. Remove from the skillet; set aside.
To the same skillet, add oil, zucchini and onion; cook and stir until vegetables are crisp-tender, about 5 minutes. Stir in sausage, tomatoes, garlic salt, oregano and pepper. Cook, uncovered, until heated through, about 10 minutes, stirring occasionally.
Drain pasta and place on serving platter. Top with sausage mixture. If desired, sprinkle with cheese.