Heat 1 Tablespoon olive oil in a large skillet or saute pan over medium heat. Add the sliced onions and cook until translucent, about 3-4 minutes. Stir in the sliced garlic and cook until fragrant, about 1 minute.
Stir in the sliced sun-dried tomatoes, the sliced zucchini, 1 teaspoon kosher salt, and 1/2 teaspoon freshly ground black pepper. Cover the skillet and cook until the zucchini is just starting to soften, about 5-7 minutes, stirring 2-3 times during cooking. Serve immediately.
Notes
If you are using dry sun-dried tomatoes, rehydrate them by soaking in water while you prep the remaining ingredients.