Makes: 6 to 8 appetizer servings
1. Prepare Watermelon Pico de Gallo: Combine all ingredients in a large bowl. Cover and chill 1 hour.
2. Prepare Blackened Tuna Nachos: Preheat oven to 350°. Sprinkle all sides of tuna with blackened redfish seasoning. Set aside.
3. Heat 1 Tbsp. oil in a large nonstick skillet over medium-high heat. Sauté onion and jalapeño pepper in hot oil 5 minutes or until softened. Stir in black beans and next 3 ingredients. Cook 2 minutes or until thoroughly heated.
4. Spread tortilla chips on a half sheet pan. Sprinkle with half of cheese. Spoon bean mixture evenly over top of cheese. Sprinkle with remaining half of cheese.
5. Wipe skillet clean; add remaining 1 Tbsp. oil, and heat over medium-high heat until hot. Add tuna steak, and sear on all sides, 4 minutes or to desired degree of doneness. Transfer to a cutting board; let stand 5 minutes.
6. Meanwhile, bake nachos at 350° for 7 minutes or until cheese melts. Remove from oven, and let stand 3 minutes. Cut tuna into thin slices; cut slices into 1-inch pieces, and arrange over top of nachos. Serve immediately with Watermelon Pico de Gallo.