1. Heat oil in a large nonstick skillet over medium-high heat. Sprinkle 1/4 teaspoon salt and 1/4 teaspoon pepper evenly over both sides of fish. Add fish to pan; cook 4 minutes on each side or until desired degree of doneness.
2. Combine coleslaw, remaining 1/8 teaspoon salt, remaining 1/4 teaspoon black pepper, tarragon, mayonnaise, lemon juice, and mustard; toss well. Arrange 1 fillet over bottom half of each roll; top with 1/4 cup slaw and top half of roll.