Pat the pork dry, rub 1-2 tablespoons of vegetable oil on the pork shoulder, then rub with the Serious Foodie spice blend. Let sit for 15-30 minutes at room temperature, or 2-3 hours in the fridge.
Transfer the pork shoulder to a slow cooker, or a Dutch oven and add the onion, garlic, jalapeño, orange, and lime juice. If you need more liquid, add some water. Cover and cook on low for at least 6 hours. If using a Dutch oven, place in the over at 250 F,
Once the meat is tender, remove from the pot and let cool slightly. Using two forks, shred the meat by pulling the forks in opposite directions. Season the meat with salt to taste. We like to de-fat the liquid in the pot by placing it in a tall container, put in the refrigerator for a few hours, and just skim off the top. Adding the meat back into the cooking liquid for a few hours, or overnight, makes for very flavorful meat.
Preheat the oven to the broil setting. If the pork looks dry, toss the pulled pork in a bit of vegetable oil - not too much. Spread the carnitas out on a rimmed sheet pan and broil until golden brown, about 3-4 minutes.
Add the carnitas, chopped cilantro, and pickled red onions to each tortilla. Serve with lime wedges.