Core the peppers, remove seeds, and cut lengthwise into narrow 1/2-inch strips.
Cut off the pineapple crown. Cut pineapple lengthwise into quarters. Trim away the core. With sharp knife, peel each quarter by cutting away the skin from the flesh in one piece (not too close to the rind), leaving a narrow "boat" which will serve as a decorative container. Cut the flesh into medium (l/2-inch) dice or triangular chunks. In large bowl, combine pepper strips and pineapple. Add vinagreta and toss to distribute. Let stand at room temperature 15 minutes to blend flavors. To serve, place a pineapple "boat" on each salad plate and arrange one-fourth of the pineapple mixture on it. Sprinkle with optional sesame seeds
In a small bowl, whisk the vinegar with the garlic and pepper; taste for seasoning; add salt to taste. Whisk in the oil, a little at a time, until well combined.