To prepare the coleslaw: Place blueberries, mayonnaise, and apple cider vinegar into a blender or food processor. Blend until smooth and set aside. In a large bowl, combine shredded red cabbage and broccoli slaw mix. Gently fold in the blueberry dressing, season with salt/pepper to taste, and place into the refrigerator until ready to use.
Preheat a gas or charcoal grill to 450°F. Brush each salmon fillet with olive oil, and generously season salmon fillets with salt and pepper. Place the salmon directly on the grill, skin side down, and cook for about 5 minutes.
Flip the salmon over and grill for an additional 2 minutes, skin-side up, or until cooked thoroughly and to your liking. Remove salmon from the grill and let rest for 5 minutes before breaking the salmon into chunks.
To assemble the tacos: Fill the warm tortillas with salmon and a serving of the blueberry coleslaw. Drizzle each taco with fresh lime juice and top with cilantro for garnish, if desired. Enjoy!