Step 1Heat the grill or broiler.
Step 2Cut the chicken breasts in half horizontally if they're thick and place them on a plate. Combine the olive oil, lemon juice and minced garlic and pour it over the chicken. Season the chicken with salt and pepper.
Step 3Grill the chicken over a medium-hot fire or broil until a meat thermometer reaches an internal temperature of 160 degrees and the breasts are lightly browned, about 15 minutes. Place the lemons cut side down on the grill until lightly browned, 1 to 2 minutes.
Step 4To serve, slice the breasts diagonally into 5 pieces. Mound the couscous on each serving plate and place a sliced chicken breast on top. Squeeze the grilled lemon on the chicken and couscous.