Cook orzo per package directions. Drain well, then transfer to large bowl; toss with oil. Meanwhile, in another large bowl, whisk together vinegar and 1/4 teaspoon each salt and pepper. Add zucchini and squash and toss to combine. Let sit until orzo is done, at least 5 minutes. With slotted spoon, transfer vegetables to bowl with orzo, leaving vinegar in bowl, and toss to combine.  Whisk pesto into vinegar, then drizzle over orzo and sprinkle with almonds.