Place egg whites in a shallow dish; place panko in another shallow dish. Dip fish in egg whites; sprinkle fish evenly with 1/4 teaspoon salt, and dredge in panko. Heat oil in a large ovenproof skillet over medium-high heat; swirl to coat. Add fish to pan; cook 3 minutes or until browned and very crispy. Turn fish over; place pan in oven. Bake fish at 450° for 7 minutes or until desired degree of doneness.
Combine remaining 1/4 teaspoon salt, tomatoes, and remaining ingredients in a bowl. Serve with fish.
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