In a small bowl, combine pineapple, green onions, green pepper, cilantro, 4 teaspoons lime juice, 1/8 teaspoon salt, and cayenne pepper.

Mix well and chill until serving time.

In a separate small bowl, combine canola oil and the remaining lime juice.

Brush the lime and oil mixture over the tilapia fillets and sprinkle with pepper and the remaining salt.

Preheat a grill pan over medium heat.

Grill the tilapia fillets, turning once, for 6 to 8 minutes, or until the fish flakes easily with a fork.