In a medium bowl, whisk together the yogurt, sour cream and mustard. Stir in the red onion, mint, lemon juice, and Tabasco and season to taste with salt and pepper. The sauce can be prepared up to 5 days ahead of time and refrigerated until needed.
Make the kibbe
Rinse the bulgur with warm water to remove any dirt and excess starch. Drain it well in a colander then scoop it into a bowl and set aside.
Bring 4 cups of water to a boil then carefully pour it over the bulgur. Cover the bowl with a tight-fitting lid or foil and let soak until the bulgur has tripled in size, 45 minutes to 1 hour.
Dump the ground beef in a large bowl. Add the hydrated bulgur, onion, scallion, garlic, oregano, mint, olive oil, salt, pepper, cayenne, and hot sauce. Mix with your hands until well blended.
Pinch off an egg-size piece of the mixture and roll it between your palms to form an oval with two pointed ends. (At this point you can refrigerate the formed kibbe in a tightly covered container for 1 day. Make sure to bring them to room temperature before frying).
Fry the kibbe
Heat the oven to 180°F (80°C). Place a wire rack on a baking and sheet and slip it inside.
Heat the canola oil in a heavy-bottomed pot with high sides until it registers 350°F (175°C) on a deep-fat thermometer. If you don't have a thermometer, lower a kibbe in the bowl of a slotted spoon into the oil; if the oil sizzles and snaps and the kibbe starts to color, you're set.
Fry the kibbe in batches, giving them plenty of elbow room, otherwise they won't cook evenly. Turn them occasionally till they're deeply brown, 3 to 5 minutes.
Using a slotted spoon, transfer the kibbe to paper towels to drain. Transfer the kibbe to the wire rack in the oven to keep warm while you finish frying the rest.
Arrange the kibbe on a large platter, or in small paper containers for a festive look, and have plenty of Yogurt-Mint Sauce on hand for dipping. If desired, drizzle the sauce with olive oil. To reheat, pop the kibbe in a 300°F (150°C) oven for 5 to 10 minutes.
Notes
Make sure to buy very lean ground meat; if the meat is marbled with fat, the kibbe won’t hold its shape when frying. Also, take the meat out of the refrigerator 30 minutes before using it so it blends with the bulgur.