For the chicken: In a bowl, whisk together oil, paprika, cumin, garlic powder, lime juice, salt, and pepper. Place the chicken breasts into the bowl and massage the marinade into the breasts. Let marinate for 20 minutes. Preheat grill or grill pan on medium heat. Grill the chicken on both sides to an internal temperature of 160 degrees using a thermometer. Set aside to rest for 2 - 3 minutes then dice small.
Rub one side of the taco shells with a very small amount of canola oil. Grill the shells on the oiled side until warmed and marked.
For the jicama: In a bowl mix together all of the ingredients. Season with salt and pepper to taste. Then set aside.
Assembling the tacos: Place the chicken on the taco shells, top with pepper jack cheese, and jicama slaw. Garnish with cilantro.
Notes
Pro tips: Butterfly the chicken: Lay the breasts down on a cutting board, using a sharp knife parallel to the cutting board slice the breasts through the middle (carefully) all the way in half.