Finely chop the lettuce and season with a little oil and salt. Grill the chicken breast fillets over a moderately hot grill for 12-15 minutes, turning frequently. Make sure the chicken is cooked through, then remove from the heat and slice thinly. Heat the tacos on the grill, a few minutes per side. Fill the tacos with chicken, lettuce, and a generous amount of TRUFFLE JALAPENO DRESSING .