Preheat the oven to 400 degrees F. Drizzle the squash with olive oil and season with salt and pepper. Spread into an even layer on a baking sheet and roast until light golden brown and cooked through, 15 to 20 minutes. Let cool.
Rinse farro and place in a medium saucepot with the water, cider, bay leaves and salt. Bring to a boil then reduce heat and simmer until tender (approx. 20 minutes). Most of the water should be absorbed, drain off any excess if needed.
In a large bowl, whisk together the oil, vinegar, dijon, orange zest, juice and honey, season with salt & pepper.
Add the farro, roasted squash, arugula, parsley, pistachios and parmesan cheese and gently toss until everything is well incorporated. Once everything is combined, taste for seasoning, adding additional salt and pepper if needed. Serve at room temperature.