Preheat oven to 350. Toast walnuts in an oven at 350 for 8 minutes or until they darken a couple of shades or toast in a dry frying pan. Let cool. Increase oven heat to 400. Mix 2 teaspoons walnut oil, balsamic vinegar 1/4 teaspoon salt and a few grinds of pepper in a medium bowl. Toss squash in the mixture. Bake squash turning once, 20 minutes or until tender but firm. Let cool. Combine 3/4 cup walnut oil, balsamic vinegar, 3/4 teaspoon salt and a few grinds of fresh pepper, and whisk well. Taste and since not all balsamic vinegar is the same, add a bit of white sugar as needed to cut the acidity to your liking. Boil pasta as directed on box, in salted water. Drain pasta but do not rinse. Immediately place pasta in a large bowl, whisk dressing again and pour half of it over the pasta. Toss the pasta with the dressing and put bowl into the refrigerator to chill. (pasta will change color because of the spices) When pasta is room temperature, add the squash, grapes, green onions and cilantro and toss to mix. Just before serving toss in the toasted walnuts and the craisins. Taste for dressing to see how much more to add and check for salt and pepper as well.