Preheat the oven to 425°F and place a sheet pan in the oven while it preheats
Add cauliflower to the hot sheet pan with oil and spices, toss to combine, and roast for about 30 minutes, tossing halfway
Pat beans dry, roughly chop them, place on a smaller sheet pan with oil and spices, and roast for 15-20 minutes until brown with crispy edges
After beans cool for 5 minutes, add arugula and pistachios and toss together, then set aside
While cauliflower roasts, make the dressing by adding all dressing ingredients to a jar with one tablespoon of water and whisk or shake to combine, adding more water as needed for desired consistency
Remove cauliflower from oven, add arugula and red onion to the sheet pan and toss
Plate the salad, top with the crispy bean mixture, dress as desired and toss to combine
