Cook the farro: Bring salted water to a boil and cook the farro according to package directions, about 25 minutes, until chewy but tender. Drain and spread on a baking sheet to cool slightly.
Preheat the oven: Preheat the oven to 400°F and line two baking sheets with parchment paper. Using two pans keeps the vegetables from crowding.
Prep the vegetables: Cut the sweet potato into even half-inch cubes and halve the Brussels sprouts. Toss each separately with 1 tablespoon olive oil, salt and pepper.
Roast sweet potato and sprouts: Spread the vegetables in a single layer on the baking sheets and roast for 22 to 25 minutes, stirring once halfway through, until the edges turn deep golden brown.
Crisp the chickpeas: Toss the drained chickpeas with 1 tablespoon olive oil and a pinch of salt. Add them to a corner of the pan for the last 15 minutes of roasting until golden and slightly dry on the outside.
Whisk the vinaigrette: In a small bowl or jar, combine 1/4 cup olive oil, maple syrup, apple cider vinegar, Dijon mustard, cinnamon and a pinch of salt. Whisk or shake until thickened and emulsified.
Fluff the farro: Once cooled slightly, fluff the farro with a fork so it doesn't clump when portioned into bowls.
Layer the bowls: Divide the farro among four bowls and top each with roasted sweet potato, Brussels sprouts and crisped chickpeas.
Add toppings: Scatter dried cranberries, pepitas and crumbled feta cheese evenly over each bowl.
Drizzle and finish: Drizzle the maple cinnamon vinaigrette generously over each bowl just before eating so the grains and vegetables stay coated.