Add chicken to gallon-size zip-top bag; add Mojo and seal bag. Massage to coat chicken in marinade; transfer to refrigerator. Marinate at least 2 hours, or until ready to grill; discard marinade.
Heat grill to medium-high heat. Season chicken lightly with Adobo. Add chicken to hot, greased grill grates. Grill, flipping once, until golden brown and cooked through (internal temperature registers 165° on quick-read thermometer when inserted into thickest part of breast), about 10 minutes. Transfer chicken to platter; tent with foil to keep warm.
Meanwhile, in large bowl, whisk together balsamic vinegar and olive oil; season with Adobo to taste. Add arugula, tomato and red onion to bowl; toss to coat in dressing.
Top chicken with arugula salad. Serve.