For the marinade, add all ingredients except chuck roll slices to a blender and puree. Add meat to a resealable bag, pour over the marinade, and allow to marinate in the refrigerator for at least 2 hours.
For the sauce, heat a skillet on medium high. Brush garlic, jalapeno, tomatoes and onions lightly with olive oil. Place in skillet until lightly charred.
Remove charred veggies and put in blender except for jalapeno. Place it in a small resealable plastic bag for 5 minutes. Then, wearing gloves, remove the charred skin, then seed and devein pepper. Add it to blender with the rest of the ingredients.
Puree sauce. Add reserved soaking liquid in 1/2 cup at a time until a nice sauce consistency is reached.
Light grill and get to a medium hot grilling temperature. Place slices of beef on grill and cook 3-4 minutes per side or until desired doneness is reached. Grill onion and peppers alongside meat, if desired. When meat is done, remove from grill, lightly cover with foil, and rest for 5 minutes.
Chop beef into taco sized pieces. Serve with grilled tortillas and your favorite taco accompaniments. Enjoy!