Step 1
Pat 3 lb. boneless pork shoulder (Boston butt), fat cap trimmed if needed, cut into 4 pieces, dry; season generously on all sides with kosher salt and freshly ground black pepper. Heat 2 Tbsp. extra-virgin olive oil in a medium Dutch oven or other heavy pot over medium-high. Working in 2 batches, cook pork, turning occasionally, until browned all over, 7–9 minutes per batch. Transfer to a plate.
Step 2
Pour off all but 2 Tbsp. fat from pot. Add four 3″ cinnamon sticks and cook, stirring, until starting to unroll, about 1 minute. Add 1 medium red onion, coarsely chopped, and cook, stirring occasionally, until softened, 5–7 minutes. Add 4 garlic cloves, smashed, and cook, stirring often, until fragrant, about 1 minute. Add 3 Medjool dates, pitted, chopped, 1 large bay leaf, ¼ tsp. cayenne pepper, and 1 tsp. Diamond Crystal or ½ tsp. Morton kosher salt; season with black pepper and stir to combine. Add one 28-oz. can whole peeled tomatoes and their juices, crushing with your hands as you go, then pour in 5 cups water; stir to combine.
Step 3
Return pork along with any accumulated juices to pot and
bring to a boil. Reduce heat, partially cover, and cook, adjusting heat as needed to
maintain a simmer, until meat is fork-tender, 2½–3 hours.
Step 4
Transfer pork to a medium bowl and shred with 2 forks; return to pot. Add two 15-oz. cans chickpeas, rinsed, and bring to a boil. Reduce heat, cover, and simmer until chickpeas are very tender, 25–30 minutes. Remove from heat and stir in 1 Tbsp. red wine vinegar. Taste stew and season with more salt and/or add vinegar if needed.
Step 5
Divide stew among bowls; top with sliced red onion and torn mint leaves.
Do Ahead: Stew can be made 1 day ahead. Let cool; cover and chill.