In a large mixing bowl, add your chicken chunks, pineapple, onion, cumin, salt, paprika, lime juice, garlic and olive oil. Toss together until well combined
Thread your chicken onto your skewers making sure to alternate with the pineapple and onion. Don't crowd the skewer!
Season your skewers with tajin, being sure to flip them over as well. Some of the tajin will fall off so don't be afraid to put a little extra on.
Preheat your grill to medium high heat. Be sure to either spray with non stick, brush with oil or use a foil grill cover.
Grill until cooked through which could take anywhere from 6-8 minutes per side. I like to use a thermometer to check.
Serve and enjoy!