Combine first 3 ingredients in a zip-top bag. Add tuna. Seal bag; marinate in refrigerator 20 minutes, turning occasionally.
Bake pizza crust at 450º for 6 minutes or until crisp.
Heat olive oil in a small skillet over medium-high heat. Remove tuna from marinade, discarding marinade. Sprinkle tuna with pepper; sear in hot oil 2 minutes on each side or to desired degree of doneness. Remove tuna from skillet, and let stand 5 minutes. Cut tuna into thin slices.
Place lettuce in a medium bowl; drizzle with 1/3 cup Ginger-Lime Dressing, tossing well. Spoon lettuce mixture over pizza crust, and top with tuna slices. Cut into wedges; serve immediately with additional Ginger-Lime Dressing, if desired.