To prepare salsa, combine first 8 ingredients in a medium bowl. Cover and chill.
To prepare the fish, combine cumin seeds, peppercorns, and 1/4 teaspoon salt in a small zip-top plastic bag. Coarsely crush the cumin seed mixture using a meat mallet or rolling pin. Sprinkle the cumin seed mixture on 1 side of each steak. Heat 1 teaspoon vegetable oil in a large nonstick skillet coated with cooking spray over medium-high heat. Add fish, crust sides down; cook for 5 minutes on each side or until fish flakes easily when tested with a fork. Serve with salsa.
