Slow Cooker Pulled Pork BBQ Crunchy Tacos

pork shoulder, trimmed of excess fat

favorite BBQ spice rub

favorite BBQ sauce

sour cream

small purple cabbage, finely shredded (a mandolin works great!)

lime

cilantro leaves

box purple crunchy taco shells

crispy fried onion straws, for garnish (totally optional)

coarse salt