Heat oil in large skillet; add onion and garlic. Cook, stirring occasionally, until onion is tender. Stir in crab meat, salsa and cilantro; cook until heated through.
Combine lettuce, bell pepper and cucumber in medium bowl.
Fill tortillas evenly with the crab mixture, then top with the lettuce mixture.
Tip: If you like cheese on your crab tacos, crumbled queso fresco would be a good choice.