In a small bowl, mix lemon juice, garlic, honey, pepper flakes and Adobo. Using a whisk, add olive oil in a slow and steady stream, mixing constantly to combine well the ingredients. Stir in the coriander; set aside.
Heat the grill to médium-high heat. (Or heat oven to 218ºC) In plate, frizzle the chicken with olive oil and sprinkle with adobo. Grill the chicken, flipping once, until dark golden Brown on both sides and cooked through, about 15 minutes. (If cooking in oven, place chicken on foil-lined baking sheet. Cook until golden Brown and cooked through, about 15 minutes). Set chicken aside to cool. Cut tinto strips.
Arrange lettuce on large serving platter. Toss with sliced chicken, avocado, grapefruit, and onions. Drizzle with dressing before serving.