Thaw fish, if frozen. In a covered small saucepan cook potatoes in enough boiling salted water to cover about 15 minutes or until tender. Drain and cool.

In a small bowl combine chipotle chile pepper, sugar, and the 1/4 teaspoon salt. Rinse fish; pat dry with paper towels. Measure thickness of fish. Sprinkle chile powder mixture evenly over both sides of each fish fillet; rub in with your fingers. Place fish on greased rack of an uncovered grill directly over medium coals. Grill for 4 to 6 minutes per 1/2-inch thickness or until fish flakes easily when tested with a fork, turning once halfway through grilling time. Cool slightly. Break fish into chunks.

In a medium bowl stir together green salsa, lime juice, and 1/4 teaspoon salt. Add potatoes, fish, green onions, and cilantro; toss gently to coat.

Divide fish mixture among tortillas. Top with sour cream; fold tortillas. Serve with lime wedges if desired. Makes 6 to 8 servings.