16 slices baguette-type French bread, cut on a diagonal, 1/2-inch thick and 2 inches long
16 small sprigs watercress OR flat-leaf parsley
Combine the cumin and paprika and rub the mixture over the chicken breasts. Coat a nonstick skillet with nonstick cooking spray and place over medium-high heat. Add the chicken breasts and cook about 4 minutes on each side, or until no longer pink in the center. Cool about 10 minutes, then slice each breast into 8 pieces, cutting slightly on the diagonal, so the chicken slices are approximately the same size as the bread slices. Set aside.
In a small bowl stir the mayonnaise, orange zest, mint and walnuts together. Spread each slice of bread with a generous tablespoon of the walnut mixture. Top with a slice of chicken, then with a sprig of watercress or parsley.