In a large bowl combine the olive oil, lime juice, scallions, bell pepper, cilantro (if using) and salt and pepper.
Add the chicken, avocado and tomatoes and toss to coat with the dressing. Taste and adjust the seasonings as needed. Transfer to a serving bowl.
Notes
Don’t worry if you aren’t in the mood to make your own chicken for this salad. A rotisserie chicken is perfect, or perhaps you have some leftover cooked chicken breasts. Just shred or cube up two cups and you are good to go.