Place chicken, onions, and garlic in a slow cooker.
In a small bowl, combine pineapple, coconut aminos, lime juice, ground ginger, red pepper flakes, salt, and pepper. Stir to mix, and then add to slow cooker.
Cook on low for 4-6 hours. Remove chicken from slow cooker and shred with two forks.
Return chicken to slow cooker, stir to mix all ingredients, and set the temperature to warm (or low) until ready to serve.
Assemble wraps with desired ingredients.