Cut the squash in half lengthwise with a sharp knife – be careful and go slowly. Scoop out seeds with a tablespoon and reserve. Preheat oven to 375°. Place squash halves cut side up on a heavy-bottomed roasting pan. Brush with olive oil and season with salt and pepper. Roast for about 45 to 50 minutes or until a fork easily punctures the flesh. If the squash seems to be drying out while baking, brush with an additional tablespoon of olive oil. Remove squash from the oven and allow it to cool just enough so you can handle it, about 3 to 4 minutes. Scrape the flesh from the squash stringy “noodles” with a sturdy fork and place in a serving bowl. Stir in pesto and tomatoes and serve.