Make the chicken: In a large bowl, whisk pineapple juice, soy sauce, ginger, agave, salt, and pepper until smooth. Place chicken in a resealable plastic bag. Pour marinade over chicken and seal bag. Marinade chicken in refrigerator at least 4 hours or overnight.
Remove chicken from marinade and discard marinade. Grill chicken over medium-high heat, turning once until chicken registers 165F, about 10-15 minutes. When chicken is cool enough to handle, slice into thin strips. Set aside.
Make the salad: In a large bowl, combine lettuce, mango, sweet pepper, avocado, and chicken strips. Set aside for a moment to prepare the dressing.
Make the vinaigrette: In a small bowl, whisk all dressing ingredients until smooth. Season with salt and pepper to taste.
When ready to serve salad, pour dressing over top and toss to combine. Enjoy!