Spray a large skillet with cooking spray and place over medium-high heat; add luncheon meat. Cook and stir until lightly browned, about 5 minutes. Add taco seasoning mix; stir to coat. Pour in water; cook and stir until water is evaporated, 2 to 3 minutes. Turn heat to low to keep luncheon meat warm.
Spray a separate skillet with cooking spray and place over medium-high heat; add 1 tortilla and cook until heated through, about 1 minute per side. Repeat with remaining tortillas.
Layer luncheon meat, lettuce, Cheddar cheese, tomato, onion, and black olives onto each tortilla.