Place 1 cup diced mango in blender and process until pureed.
Add remaining ingredients except for olive oil and blend until smooth. With the blender running on low speed, slowly pour in olive oil and blend until emulsified. Refrigerate until ready to serve.
Brush each side of chicken breasts with olive oil and season with salt and pepper. Grill chicken over medium high heat until done and juices run clear. Allow to rest for 5-10 minutes, then cut into bite size pieces.
In a large salad bowl toss salad greens with English cucumber, red bell pepper, red onion slices, and diced mango. Add cooked chicken and toss gently. Serve with mango vinaigrette.