Combine the soy sauce, vinegar, black pepper and sliced onion in a large bowl. Add the chicken and cover the bowl. Refrigerate for at least 8 hours or up to overnight to marinate.
Prepare a charcoal grill with natural mesquite charcoal to high heat. Grill the chicken for 10 minutes, then rearrange the pieces to make grill marks and grill 10 more minutes. Flip and cook for a final 10 minutes.
Arrange the chicken on a sheet pan and cool in the refrigerator, about an hour.
Chop the chicken into 1/2-inch cubes and place in a large mixing bowl. Add the green onions, diced yellow onion, coconut, chile pepper and lemon juice. Toss to combine. Refrigerate.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.