Serve this cold or at room temperature—perfect for a picnic or barbecue.
- 8 ounces orzo (about 1 1/3 cups)
- 6 1/2 tablespoons extra-virgin olive oil, divided
- 4 tablespoons red wine vinegar, divided
- 2 medium zucchini or summer squash (about 9 ounces total), cut lengthwise into 1/4-inch-thick slices
- 1 red or yellow bell pepper, quartered
- 3 tablespoons purchased pesto
- 2 tablespoons fresh lime juice
- 1 pound uncooked large shrimp, peeled, deveined
- 2 heirloom tomatoes (8 to 10 ounces total), cored, cut into 1/2-inch cubes (about 2 cups)
- 1/2 cup thinly sliced fresh basil leaves plus sprigs for garnish
- 1 8-ounce ball fresh mozzarella cheese, cut into 1/2-inch cubes
- Cook orzo in large pot of boiling salted water until tender but still firm to bite, stirring occasionally. Drain. Rinse with cold water; drain well. Transfer to large bowl and toss with 1 tablespoon oil.
- Prepare barbecue (medium-high heat). Whisk 2 tablespoons oil and 2 tablespoons vinegar in small bowl. Brush zucchini and bell pepper with oil mixture, then sprinkle with salt and pepper. Whisk pesto, lime juice, remaining 3 1/2 tablespoons oil, and remaining 2 tablespoons vinegar in small bowl for pesto vinaigrette. Place shrimp in medium bowl. Add 2 tablespoons pesto vinaigrette; toss to coat.
- Grill zucchini and bell pepper until crisptender, about 3 minutes per side for zucchini and 4 minutes per side for bell pepper. Transfer to work surface. Sprinkle shrimp with salt and pepper; grill until charred and cooked through, 2 to 3 minutes per side. Place shrimp in bowl with orzo. Chop zucchini and bell pepper; add to bowl with orzo. Add remaining vinaigrette, tomatoes, sliced basil, and mozzarella; toss to combine. Season to taste with salt and pepper. DO AHEAD: Can be made 2 hours ahead. Cover; chill.
- Garnish with basil sprigs and serve cold or at room temperature.