In a large bowl, stir together garlic, 1 tablespoon oil, 1 tablespoon lemon juice, salt, and pepper. Add shrimp and toss.
Heat a grill pan or large skillet over medium-high heat. Add shrimp and sear, turning once, until shrimp turns pink and is cooked through, 2-3 minutes.
In a small bowl, whisk together remaining 2 tablespoons olive oil, remaining 1 tablespoon lemon juice, and Dijon mustard. Add salt and pepper to taste.
When cool enough to handle, roughly chop shrimp.
In a medium bowl, toss lettuce mix with 2 tablespoons dressing.
To serve, lay wraps on work surface. Lay down a bed of lettuce mix. Top with shrimp, red onion, cucumber, and cherry tomatoes. Drizzle with more dressing if desired and roll up.