Preheat oven to 425. Line a rimmed baking sheet with unbleached parchment paper.
Scrub carrots (peeling is optional) and cut into 2" pieces on the diagonal. Trim fennel and thinly slice.
Place veggies on prepared baking sheet and toss with oil and spices.
Roast for 30 minutes until soft and beginning to caramelize.
Meanwhile, whisk together dressing ingredients. When carrots come out of oven, toss with dressing and set aside.
When carrots have cooled slightly, toss in arugula and serve at room temp.
Notes
MAKE AHEAD: roast the carrots and toss with dressing. You can refrigerate at this point until ready to serve....either bring to room temp or gently heat in 300 degree oven for 10 minutes. Add in the arugula when you're ready to serve.