Cut hot dogs into 1½ to 2-inch chunks. Toss with yellow mustard in a large bowl until lightly coated. Mix together brown sugar, smoked paprika, garlic powder, onion powder, black pepper, salt, chili powder, and cayenne. Sprinkle rub over hot dogs and toss to coat evenly. Let sit 10 to 15 minutes.
Preheat smoker to 250°F with apple or cherry wood. Place hot dog chunks on smoker grates spaced ½ inch apart. Close lid and smoke for 45 to 60 minutes until edges darken, casings blister, and bark develops.
While hot dogs smoke, make glaze: Combine honey, BBQ sauce, Sriracha, butter, soy sauce, and vinegar in saucepan over medium heat. Whisk until butter melts and mixture combines. Simmer 2 to 3 minutes. Remove from heat.
Transfer smoked hot dogs to aluminum foil pan. Pour warm glaze over hot dogs and stir gently to coat. Cover pan loosely with foil. Return to smoker at 250°F and braise covered for 45 minutes.
Remove foil cover from pan. Continue cooking uncovered for 20 to 30 minutes, stirring every 10 minutes, until sauce thickens and coats hot dogs with sticky, lacquered glaze. Edges should look candied and glossy.
Remove from smoker and let cool 3 to 5 minutes. Transfer to serving platter and sprinkle with sesame seeds and green onions if using. Serve with toothpicks.
Notes
Use premium all-beef hot dogs with natural casings for best texture and flavor. Cut hot dogs into 1½ to 2-inch chunks rather than smaller pieces to prevent drying. Yellow mustard acts as binder for rub; flavor cooks off during smoking. Apple and cherry woods work best; avoid hickory and mesquite which can be too strong. Don't skip the covered braising phase which allows glaze to penetrate and prevents drying. Stir every 10 minutes during final uncovered phase to ensure even coating and prevent burning. Glaze should thicken to sticky consistency that clings to hot dogs. Serve warm rather than hot for best glaze texture.
Storage: Refrigerate leftovers up to 4 days in airtight container. Reheat gently in covered pan in 300°F oven for 10 to 15 minutes or microwave at 50% power.