How to Make It
Preheat oven to 425°F. Heat 2 tablespoons oil in an ovenproof skillet over medium-high. Add fennel wedges; cook until one side is caramelized, 4 to 5 minutes. Flip fennel; place pan in oven. Roast at 425°F, stirring occasionally, 12 minutes. Place fennel in bowl; toss with 1/2 teaspoon black pepper and 1/4 teaspoon salt.
Combine fennel seeds, coriander, cardamom, paprika, remaining 1 teaspoon black pepper, and remaining 3/4 teaspoon salt. Coat tuna with 1 tablespoon oil, then coat with spice mixture. Heat 2 tablespoons oil in a skillet over high. Cook tuna to desired degree of doneness, about 2 minutes per side for medium-rare. Cut steaks in half diagonally.
Section orange over a bowl; reserve juices. Combine orange sections, 1 tablespoon fennel fronds, and remaining 2 tablespoons oil. Top orange mixture and fennel wedges with Aleppo, if desired, and remaining fennel fronds. Serve with tuna.