Place the tuna in a medium bowl and flake it gently with a fork. Add the olive oil, lemon juice, salt, and black pepper to the tuna and mix until well combined.
Stir in the red onion, cucumber, tomato, olives, and parsley until combined.
Portion the spinach onto the tortilla. Top with tuna mixture, fold in the sides and roll up tightly. Cut in half.
Combine sparkling water and lemon slices. Serve over ice if preferred. .
Serve the wrap with apple slices, cheese, pickle spears, and lemon sparkling water.