Add canola oil to a heavy bottomed pot with a tight fitting lid and put it over medium heat. Add the onion and garlic and saute until softened, about 4 minutes. Add the chicken thighs, skin side up, fitting them in tightly. Add the thyme and rosemary sprigs, season with salt and pepper, to taste, and pour in 1/2 cup water. When it comes to a boil, lower the heat, cover and simmer for 1 hour. Remove the chicken from the pot and let it cool. When it is cool, shred the meat, discarding the skin and bones. (Reserve the meat from 2 thighs for Round 2 Recipe Chicken Tacos with Cucumber Salsa.)
In a large bowl combine the sugar, vinegar, red pepper flakes and mix together. Shred half of the cabbage and add it to the bowl, then season with salt and pepper, to taste. (Reserve the remaining cabbage half for the Round 2 Recipe Chicken Tacos with Cucumber Salsa.) Toss to coat all of the cabbage, then cover and refrigerate until ready to use.
In a large bowl, whisk together the mayonnaise, barbecue sauce, mustard, and hot sauce. Taste and adjust the seasoning with salt and pepper, to taste. Add the shredded chicken and toss to coat.
Divide the shredded chicken evenly among each roll bottom. Top with some of the cabbage, cover with the roll top, and insert a toothpick to hold it all together. Arrange on a serving platter and serve.