How to Make It
In a baking dish, rub the chicken with the jerk paste and the 1 tablespoon of olive oil and season with salt and pepper. Cover and refrigerate for 2 hours.
In a small bowl, whisk the mayonnaise with the lime juice, garlic and cilantro and season with salt and pepper.
Light a grill. Grill the chicken over high heat, turning once, until well-browned and cooked through, about 6 minutes. Lightly brush the tortillas with oil and grill just until pliable and lightly charred, about 10 seconds per side.
Cut the chicken into strips and arrange on the tortillas. Top with the watercress and drizzle with the dressing. Roll up the tortillas burrito-style and serve.