Begin by washing the sweet potatoes (no need to peel). Slice them into medium sized wedges about 1-2 cm wide, trying to get each in a relatively similar size and shape. Add to a large bowl and drizzle with a few TBS of neutral oil, tossing to coat. Sprinkle on 1 teaspoon salt, few twists of black pepper, and cumin if using. 

Heat a grill to high (if you do not have access to a grill, see notes).  Lay sweet potatoes down on grates and let cook for 4-6 minutes, until char marks form. Flip and cook a few more minutes on the other side. You want to ensure they are fully cooked through, and depending on their specific positioning on the grill this could take some time. 

While sweet potatoes are cooking, add yogurt, lime juice, cayenne/red pepper, chopped herbs, and a pinch of salt and pepper to a blender. Add some water to thin to your liking. I normally add at least ½ cup water to get something nice and saucy (which helps coat the potatoes later). Set aside.

If you're making crispy farro, add it to a lined baking sheet and toss with neutral oil. Broil in the oven for about 5 minutes, until you hear small popping noises. Remove and let cool (it will harden more out of the oven). If you are using nuts, coat with a bit of oil until lightly browned and fragrant - about 5-7 minutes. They can burn easily! Set aside.

To assemble salad, plate sweet potatoes on a platter and drizzle with dressing to coat (you may have some left over). Sprinkle crispy farro on top and then add chopped herbs. Serve immediately. Store any leftovers in a sealed container in the fridge for a few days.