Cube up the cooked prime rib into small bite size pieces and season with taco seasoning.
Preheat the griddle to a medium heat and drizzle some olive oil on the flat top.
Drop the seasoned meat onto the hot grill and heat it up. Flip it a few times to get a nice crust on all sides without burning them. No need to check temperature, the meat is already cooked.
Place the roma tomatoes, onion, jalapeno and garlic cloves on the hot griddle to get a nice char. Next transfer them to a blender and close the lid to allow the veggies to steam.
Add 2 chipotle peppers in adobo sauce, taco seasoning and lime juice. Blend the ingredients until the desired consistency. Just before you are done, drop in a handful of fresh cilantro. Blend enough to have chopped pieces of green cilantro visible in the salsa.
Warm up the tortillas on the griddle.
To assemble the leftover prime rib tacos, add a generous scoop of the grilled leftover prime rib onto the tortilla, pour the homemade red salsa, top with chopped white onion and cilantro and enjoy!