Trim pork of fat and silverskin and cut crosswise into 1/4-in. slices. Arrange slices between layers of plastic wrap and, with a meat mallet or heavy rolling pin, pound until paper thin.
Prepare grill for direct high heat (about 500°; you can hold your hand 5 in. above cooking grate only 2 to 3 seconds). In a bowl, mix fish sauce, soy sauce, oyster sauce, garlic, sugar, and chili sauce. (If you like, double the marinade and save half to use as a sauce.) Add pork and toss to coat. Let stand 10 minutes. Weave strips of meat onto eight 10-in. metal or soaked wooden skewers.
Halve each eggplant crosswise, then lengthwise; score each piece on flesh side a few times with a sharp knife. Add eggplant to pork marinade and turn to coat on all sides.
Put skewers on center of grill and surround with pieces of eggplant, skin side down. Cover and cook 2 minutes. Turn meat over, cover, and cook 2 minutes more. Remove meat from grill. Cook eggplant, covered, turning often, 4 to 6 minutes, or until eggplant is very soft but not burned.
Note: Nutritional analysis is per serving.