In a large bowl, combine the buttermilk, garlic powder, onion powder, paprika, salt, and black pepper. Add the chicken tenders, ensuring they are fully submerged. Cover and refrigerate for at least 1 hour or overnight for best results.

In a shallow dish, mix together the flour, cornmeal, and cayenne pepper (if using). Remove the chicken from the buttermilk and let excess liquid drip off. Dredge each tender in the flour mixture, pressing lightly to adhere.

In a large skillet, heat about 1 inch of vegetable oil over medium heat until it reaches 350°F. Carefully add the chicken tenders in batches, frying for about 4-5 minutes on each side or until golden brown and cooked through. Use a slotted spoon to transfer them to a paper towel-lined plate to drain excess oil.

In a small bowl, combine the mayonnaise and Dijon mustard to create a sauce.

To assemble the sandwiches, place a fried chicken tender in each hot dog bun. Top with shredded lettuce, diced tomatoes, and a generous drizzle of the mayonnaise-Dijon sauce. Add pickles for garnish.

Serve immediately and enjoy your Bird Dog Sandwich!