Place the pork shoulder and chopped garlic into a big bowl. Sprinkle the meat with salt, cumin, chili powder, black pepper, cinnamon, and cayenne. With your hands, rub the seasonings into the meat.
Transfer seasoned pork to the slow cooker. Add in lime juice, orange juice, and beer. Cover the pot and cook on low for 8 hours.
After 8 hours, transfer the meat to a large bowl and shred it apart using two forks. The pork should fall apart easily.
Next, preheat broiler and line a baking sheet with aluminum foil. Spread the pork into an even layer and broil for 5 to 10 minutes, rotating the pan, until the pork is evenly crisped.
While the pork crisps up, mix together the ingredients for Summer Peach and Garden Tomato Salsas.
When ready to eat, warm each tortilla individually by grabbing with a set of tongs and placing directly over an open flame (a gas stove or grill works great). When warming, carefully rotate the tortilla charring the edges evenly. If you don’t have access to a gas stove or hot grill, dampen each tortilla with water and heat in a hot skillet, flipping once. Wrap warmed tortillas in a kitchen towel until serving time.
Wrap carnitas in charred tortillas and top with peach or tomato salsa, a squirt of fresh lime juice, and a hit of hot sauce.
For the salsas:
Mix together all the ingredients but the tomatoes and peaches together in a big bowl, then divide in two.
To one bowl, add tomatoes. To the other, add the peaches. Serve with the tacos.