In a medium bowl, mix olive oil, garlic, Mrs. Dash seasoning, salt, and lemon juice. Whisk together well.
Place chicken in a gallon size, zip top bag and pour marinade over chicken. Let marinade for 30 minutes.
Preheat grill to high heat. Place chicken on hot grill, sear one side and then turn to sear the other side. Turn the heat down to about 325 degrees and cook until chicken is 160 degrees on a digital meat thermometer.
Remove chicken from grill, cover with foil and let rest for 5 minutes.
Slice chicken against the grain. Serve with corn and/or flour tortillas, shredded cheese, lettuce, tomatoes, diced red onion, sprigs of cilantro, salsa, sour cream and guacamole.