In a large bowl, combine mixed greens, cherry tomatoes, sliced cucumbers, and diced red onions.
In a separate bowl, make the dressing by whisking together olive oil, lemon juice, Dijon mustard, salt, and pepper.
Pour the dressing over the salad ingredients and toss gently to coat.
Top the salad with crumbled Stilton cheese and crispy bacon bits.
Serve immediately and enjoy!