Firm tilapia can stand up to the simple yet robust spice rub here. Double the basil-mayo mixture and use as a veggie dip or sandwich spread for lunch.
Combine paprika, 1/2 teaspoon salt, cumin, and ground red pepper in a bowl. Rub spice mixture evenly over fish pieces. Heat oil in a large nonstick skillet over medium-high. Add fish; cook 2 minutes on each side or until done.
Combine remaining 1/4 teaspoon salt, mayonnaise, yogurt, basil, juice, and 1/2 teaspoon water in a bowl. Top tortillas evenly with carrot ribbons, radishes, avocado, fish, and mayonnaise mixture. Serve with lime wedges.