Simmer the farro in lightly salted water until tender. Drain, rinse lightly and let cool.
Combine the apple cider vinegar, sugar and some salt and pepper in a pot and bring to a boil. Pour over the raisins and let sit until they bloom and taste pickled. Let cool, and then drain, reserving 2 tablespoons of the liquid.
Clean the leeks by discarding the leafy tops, rinsing, cutting in half, and then rinsing again. Cut across like half-moons, rinse again, and then toss with the olive oil and some salt and pepper. Roast until some are slightly browned, 10 to 15 minutes. Stir the navel orange juice and zest into the farro. Add the reserved raisin liquid, roasted leeks, pickled raisins, parsley and blood orange zest. Mix well, and then add salt and pepper to taste. Fold in the blood orange segments and arugula right before serving. Garnish with the pistachios.