While pasta is cooking, heat olive oil in a large skillet over medium heat. Add garlic and red pepper flakes (if using) and cook for 1 minute, or until fragrant.
Add zucchini and cook for 5-7 minutes, or until tender. Stir in diced tomatoes, salt, and pepper.
Drain pasta and add it to the skillet with the tomato zucchini sauce. Toss to combine.
Serve immediately.
Notes
Garnish with fresh basil and grated Parmesan cheese, if desired.