If you’re using bamboo skewers, make sure to soak them in a shallow baking dish filled with water for at least 30 minutes. (This will prevent them from catching fire on the grill.)
Make the marinade. In a medium bowl, whisk together the vinegar, olive oil, garlic, salt, and black pepper. Transfer 3 tablespoons of the marinade to a separate small bowl and set aside (this will be used for this zucchini).
Add the shrimp to the medium bowl with the marinade and toss to coat. Cover the bowl and refrigerate for 30 minutes.
Pre-heat a grill or grill pan over medium-high heat.
Meanwhile, bring a large pot of salted water to a boil. Cook the orzo al dente according to the package directions. Reserve ½ cup of the pasta water to be used later (if needed). Drizzle the orzo with a little bit of olive oil, tossing to coat, to prevent the pasta from sticking together while you prep the zucchini and shrimp.
Remove the shrimp from the marinade, and thread 6 to 7 shrimps onto each skewer. (If your skewers are small, thread fewer shrimp per skewer.) You want the skewer to pierce each shrimp twice, once just above the tail shell and once near the head, to form a tight c-shape.
Pat the zucchini planks dry and brush on both sides with the reserved marinade. Season with extra black pepper and a pinch of salt. (Be very careful with the salt! The zucchini will be added to the orzo and Tomato Basil Sauce, which have plenty of salt.)
Grilling time. Grill the zucchini for 3 to 4 minutes per side until just tender (you want to keep it relatively firm). Grill the shrimp skewers for about 2 minutes per side, until the shrimp are opaque throughout.
Cover the shrimp with aluminum foil to keep them warm while you finish preparing the orzo. Slice the zucchini crosswise at a slight angle into ¾-inch pieces.
In a medium sauté pan or Dutch oven, warm the Tomato Basil Sauce over medium-low heat. When the sauce is warm, stir in the orzo and zucchini. If needed, add a little bit of the reserved pasta water to loosen the sauce slightly.
Transfer the orzo to a serving platter or individual plates/bowls. Top with the shrimp and garnish with fresh basil and crushed red pepper (if using). Serve warm.