Start by cooking the shrimp in a large pan with a tablespoon of olive oil over medium heat. As the shrimp turn pink and start to curl, you'll know they're done - this should take about 2-3 minutes per side.

Remove the cooked shrimp from the pan and set them aside to cool. In the same pan, add the sliced red onion and cook for an additional 2-3 minutes, or until it's translucent and starting to caramelize - you'll know it's done when it's soft and fragrant.

In a large bowl, combine the mixed greens, cherry tomatoes, cucumber, parsley, and dill. The freshness of the herbs and the crunch of the vegetables will add a nice texture to the salad.

In a small bowl, whisk together the olive oil, lemon juice, and Dijon mustard to make the dressing. The tangy flavour of the dressing will complement the sweetness of the shrimp and the freshness of the herbs.

Add the cooked shrimp and red onion to the bowl with the mixed greens and pour the dressing over the top. Toss everything together to combine, making sure the shrimp and vegetables are evenly coated with the dressing.

Season the salad with salt and pepper to taste, then cover and refrigerate for at least 30 minutes to allow the flavours to meld together. As the salad chills, the flavours will meld together, and the shrimp will absorb the dressing - you'll know it's ready when the flavours are balanced and the shrimp are tender.