Heat a large skillet over high heat. While heating, salt and pepper all sides of pork roast.
When pan is very hot, place pork roast in pan and sear meat on all sides until golden brown.
Transfer to oven safe vessel that can be tightly covered. Pour beer over pork along with juice of 2 limes. Cover and cook in 350 degree pre-heated oven.
Cook for 90 minutes (or until tender).
While pork is cooking, prepare pineapple salsa to add to pork.
Mix diced pineapple with diced pepper, diced onion and juice from remaining 2 limes. Set aside.
Remove pork from oven and using two forks, shred pork into bite-sized pieces. While still hot, add vinegar, sugar, garlic cloves (crushed) and crushed red pepper. Mix thoroughly.
Add ½ of the pineapple mixture and return to oven, uncovered for 15 minutes.
Mix pork mixture and add ½ of the cilantro to pork and the other half to remaining pineapple mixture.
Place pork mixture onto a fresh brioche bun and top with fresh pineapple mixture. Serve Warm.