Cucumbers should be finely dice, unpeeled.Trim the chicken breast halves of all fat and gristle and separate the tenderloin. Mix soy, oil, honey, lime juice, salt, and cayenne in a shallow dish just large enough to hold the chicken in one close layer. Marinate the chicken in this mixture for 1 hour at room temperature or for several hours the refrigerator, turning several times. Grill the chicken breasts for 3 to 4 minutes per side, the tenderloins about 2 minutes per side. The chicken may also be sauteed over moderate heat in a skillet lightly filmed with oil. The bottom of the skillet will darken as the honey caramelizes but is easily cleaned. Cut the breasts in thick slices and fan on dinner plates, placing the tenderloins along side. Spoon the salsa over the top and drizzle with the mayonnaise. MANGO SALSA Slice the mango flesh from each side of the pit. One half at a time, make an inch cut just inside the skin, then score the flesh in 3/8-inch cubes. Turn skin inside out and free the mango flesh with the knife. Cut the cubes in inch dice, reserving any mushy pieces for some other use. You should end up with about 1 1/2 cups. Combine mango with all remaining ingredients and let sit 30 minutes to blend flavor. Note: 1 1/2 Cups peach or papaya dice may be substituted for the mango.