Preheat oven to 375 degrees F (190 degrees C). Grease a baking sheet.
Combine vital wheat gluten, onion powder, garlic powder, and paprika in a large bowl.
Mix 1/2 cup hot water and bouillon cube together in a small bowl. Pour 1 1/2 cups water and the bouillon mixture over the vital wheat gluten mixture and mix together to form a dough.
Dust work surface with flour. Turn dough out onto work surface and pat into a 6-inch square.
Heat tahini in a small microwave-safe bowl until warmed through, about 30 seconds. Spread half of the tahini over the dough with your fingers. Flip dough over and repeat with remaining tahini on the other side. Cut the dough into 1x3-inch strips. Transfer strips to baking sheet.
Bake in the preheated oven until golden brown on the bottom, 10 to 15 minutes. Flip strips and bake until second side is golden brown, about 10 minutes more. Remove from oven and coat with barbecue sauce. Return to the oven and bake until flavors combine, about 5 minutes more.