In a large pot, bring water to a boil. Add 1 teaspoon of salt and the shrimp. Cook the shrimp for about 2-3 minutes, or until they are pink and opaque.
Drain the shrimp in a colander and rinse them under cold water to stop the cooking process. Allow them to cool.
In a large mixing bowl, combine the mixed greens, cherry tomatoes, cucumber, red onion, and chopped cilantro.
In a small bowl, whisk together the lemon juice, mayonnaise, Dijon mustard, olive oil, salt, and black pepper until well blended.
Add the cooled shrimp to the vegetable mixture. Pour the dressing over the salad and toss gently to combine all ingredients.
Serve immediately, or chill for 30 minutes in the refrigerator for a colder salad.