In 10-inch nonstick skillet, heat oil over medium-high heat.
Add zucchini, yellow squash, bell pepper and onion; cook about 5 minutes, stirring frequently, until crisp-tender.
In large bowl, toss couscous, vegetable mixture, pesto and vinegar.
Serve warm or cool.
Notes & Wine Advice
Couscous is on the most-wanted list because it’s versatile, tastes great and is fast to fix—it only takes 5 minutes! This tiniest form of pasta is granular semolina, a staple of North African cuisine.