Make the dressing in a small pan. Whisk together the olive oil, vinegar, garlic and dijon. Heat slowly over medium heat, season with salt and pepper, whisking until slightly thickened. Keep warm.
Saute bacon over medium heat until crisp. Add shrimp to the pan and stir fry just until heated through.
Arrange the spinach amd lettuce on 4 plates. Place the shimp and bacon over the greens and drizzle with the warm dressing. Serve immediately with crustly bread to soak up the juices.