Cook pasta in boiling salted water in a Dutch oven until al dente, about 11 minutes.
Reserve 1 cup pasta water; drain pasta. Set pasta water aside. Return pasta to Dutch oven.
Meanwhile, heat olive oil in a large skillet over medium heat.
Add zucchini, bell pepper, and garlic. Cook, stirring occasionally, until just softened, about 5 minutes.
Stir in scallions, and lemon zest and juice. Cook 2 minutes more. Remove from heat.
Add vegetable mixture to pasta in Dutch oven.
Add cherry tomatoes, sundried tomatoes, salt, and pepper; stir gently to combine.
Add pasta water as needed, ¼ cup at a time, to loosen pasta mixture.
Season pasta mixture with additional salt, to taste.
Garnish servings with fresh herbs.