Step 1

Rinse tuna; pat dry. Sprinkle with 2 teaspoons of the Cajun seasoning; rub in with your fingers.

Step 2

Coat a medium nonstick skillet with cooking spray; heat skillet over medium-high heat. Add tuna; cook 4 minutes or until desired doneness, turning once.

Step 3

In a medium bowl combine ranch dressing and the remaining 1 teaspoon Cajun seasoning. Add lettuce; stir to coat.

Step 4

To serve, break tuna into bite-size pieces. Divide lettuce mixture between two plates; top with tuna and vegetables.