To make the vinaigrette, whisk together the rice wine vinegar, mustard, garlic, pinch of salt, and pepper; slowly pour in 2/3 cup olive oil, whisking constantly. Pour into a jar with a tight-fitting lid to transport it to the picnic.
Adjust oven rack to highest position and turn broiler on high. Toss zucchini and bell pepper with 2 tablespoons olive oil and salt and pepper to taste, and arrange on a large baking sheet with sides. Broil until spotty brown, 8 to 10 minutes, turning zucchini slices and pepper halves once. Set aside in a large bowl to cool, then cut into bite-sized pieces.
Bring 1 gallon of water and 2 tablespoons of salt to boil. Add pasta; boil using package times, until just tender. Drain thoroughly (do not rinse) and dump onto the baking sheet. Set aside to cool.
Put vegetables, pasta and remaining ingredients (except dressing) in the bowl or a gallon-sized zipper bag (can be refrigerated for several hours). When ready to serve, add dressing; toss to coat.