Peel the sweet potatoes and grate them on the large holes of a box grater or with the grater attachment to a food processor.
You should have about 4 cups.
Place the grated sweet potato in a large bowl and add the onion, sifted chickpea flour, cornstarch, eggs, harissa, paprika, salt, and pepper.
Stir well until combined (the harissa will want to clump, so make sure it gets evenly distributed throughout the batter).
Heat a film of oil in a wide skillet set over medium heat until it shimmers.
Drop ¼ cup scoops of batter into the hot oil, flattening slightly (a spring-loaded ice cream scoop works well).
Fry until deeply golden on the first side, 2-3 minutes, then flip and cook on the second side until golden and cooked through, 2-3 more minutes.
The heat should be low enough that the latkes cook through by the time they're golden on the outside. Remove the cakes to a cooling rack lined with paper towels; this will drain the cakes while helping them stay crisp. (If making these for a crowd, you can place the cooling racks on baking sheets and place in a 250ºF oven to keep warm.)
Repeat with the remaining batter, adding oil to the pan as needed.
Place the latkes on plates and top with spoonful of yogurt sauce, a sprinkle of pomegranate arils and a few mint leaves. Serve immediately.
The latkes are best when fresh out of the pan, but they can be reheated in a hot skillet until crispy and heated through. Extras will keep, refrigerated airtight, for up to a day or two.