Preheat the oven to 220 degrees. Scrub the sweet potato clean, prick it deeply in a few places with a fork, and rub it with a tablespoon of olive oil and coarse salt. These prick holes allow steam to escape; without them, pressure builds up under the skin and the potato bursts open. Place it on a baking sheet and bake for fifty to sixty minutes until completely soft and some syrupy juice has run out onto the sheet.
Rinse the chickpeas, drain them, and pat them dry. Mix them with a tablespoon of olive oil, the cumin, smoked paprika, cinnamon, and salt. Slide them onto the baking sheet next to the potato for the last twenty minutes and shake them halfway through, until they are crispy and dark.
Stir the yogurt with the tahini, grated garlic, the juice of half a lemon, and salt. Keep stirring if the mixture curdles at first, as tahini will eventually bind it into a smooth sauce.
Dry-toast the pumpkin seeds in a frying pan until they pop.
Cut the sweet potato open lengthwise and push the ends toward each other so the fluffy flesh pops up. Spoon in the yogurt-tahini, top with the chickpeas, and place the arugula alongside with the remaining olive oil. Garnish with the pumpkin seeds, parsley, and mint.