How to Make It
Shave carrots into ribbons with a vegetable peeler. Combine carrots, onion, vinegar, water, and sugar in a medium bowl; let stand 15 minutes. Drain and discard pickling brine.
Preheat grill to medium-high heat.
Place hot dogs on grill rack coated with cooking spray; grill 6 minutes, turning occasionally.
Spread each hot dog bun with 1 1/2 teaspoons mayonnaise. Place 1 hot dog on each bun; top evenly with carrot ribbons and onion. Top each with 3 fresh jalapeño slices and 1 teaspoon cilantro leaves.