1. In a food processor, combine the tomatillos, onion, cilantro, jalapeno, salt, and sugar. Pulse until finely chopped, then stop and scrape down the sides. Continue processing until just chunky. Refrigerate until serving.
2. Set one of the hot dogs on a work surface. Insert an 8-inch wooden skewer through the center of the hot dog so it's parallel with the surface. Using a small knife, make a slice across one end of the hot dog toward the other end at a 45-degree angle until it reaches the skewer. Turn the hot dog and slice with your knife in the same direction on a 45-degree angle, working your way down the hot dog. Continue turning and slicing until you reach the other end of the hot dog. Remove the skewer, transfer to a platter and repeat with the remaining hot dogs.
3. Grill the hot dogs on a covered grill directly over medium-high heat for 4 to 5 minutes or until heated through and hot dogs have char marks, turning occasionally. Remove to a clean plate. Add the buns to the grill, cut sides down. Grill for 30 to 45 seconds or until toasted. Serve the hot dogs in the buns topped with salsa verde.