In a large mixing bowl, whisk together 2 tablespoons of olive oil, lime juice, chili powder, cumin, paprika, salt, and pepper.
Add chicken thighs to the bowl, coat thoroughly, and marinate for 20 minutes.
Preheat a grill or grill pan to medium-high heat (approximately 400°F).
Brush pineapple rings and red onion rounds with the remaining 1 tablespoon of olive oil.
Grill the chicken for 6-7 minutes per side or until the internal temperature reaches 165°F. Remove from heat and let rest for 5 minutes.
Grill the pineapple and onion for 2-3 minutes per side until distinct char marks appear.
Finely dice the grilled pineapple and onion. Transfer to a bowl and toss with minced jalapeño and cilantro to form the salsa.
Warm the corn tortillas on the grill for 30 seconds per side.
Slice the chicken into thin strips.
Assemble tacos by placing chicken in tortillas and topping with a generous portion of grilled pineapple salsa and a squeeze of fresh lime.