COMBINE all the ingredients for the marinade in a jug. Pour half of it into a shallow bowl to marinate the chicken, while saving half of it for the dressing. Chill the saved dressing.
MARINATE the chicken for at least an hour or two. You may also do this the night before and have it marinate overnight for best results.
GRILL the marinated chicken with some olive oil on a heated grill pan. Make sure the chicken is at room temperature if ever you marinated it overnight. Cook for about 5-6 minutes per side depending on the thickness of your chicken pieces, or until it's cooked all the way through. Once chicken is done, set aside. Grill for a few minutes the red capsicums and the asparagus for about 3-4 minutes, just enough to get a good char on them.
ASSEMBLE the lettuce, tomatoes, grilled veggies, and sliced avocados on a salad bowl. SLICE the grilled chicken and top it on the veggies. POUR the chilled dressing over the salad. Season more with salt and pepper as desired.