Position racks in upper and lower thirds of oven. Preheat to 400F. Line 2 large baking sheets with foil.

Boil apple juice with vinegar and garlic in a small saucepan. Boil until reduced to 1/4 cup, about 10 min. Remove from heat and whisk in 3 tbsp oil and mustard.Cut a large, shallow slit through the skin of squash. Microwave on high to make it easier to cut, 3 to 5 min. Slice unpeeled squash in half and discard seeds. Cut into 1/3-in.-thick slices. Toss with remaining oil, honey and salt until coated. Spread out on prepared baking sheets. Roast until just tender and edges are starting to brown, about 15 min.

Divide arugula among plates. Top with warm squash. Drizzle with dressing. Top with feta, pepitas and cranberries.