Fill a medium saucepan with water and bring it to a boil over high heat. Add the rice and return to a boil. Cook, uncovered, until the rice grains are cooked and tender but still a little chewy, 20 to 25 min. Drain the rice through a sieve and rinse with cold water to stop the cooking. Set aside.
While the rice is cooking, purée the raisins, 1/4 cup of the oil, and the vinegar in a blender, scraping the jar as needed, to make a thick, smooth vinaigrette.
Heat a 10-inch skillet over medium- high heat and toast the pistachios, stirring frequently, until they brown in spots and give off a strong nutty aroma, about 2 min. Transfer them to a cutting board. When cool enough to touch, chop them coarsely.
Heat the remaining 2 Tbs. oil in the same skillet over medium-high heat until very hot. Stir-fry the onion and garlic until honey brown, 2 to 3 min. Scrape this into a large bowl along with the pistachios, vinaigrette, chickpeas, bell pepper, salt, and red chile flakes. Add the rice to the bowl and fold the ingredients together. The salad can be served at room temperature or chilled. Just before serving, fold in the basil, taste, and season with more salt, if you like.