Preheat outdoor grill. In a small bowl combine oil, vinegar, salt and black pepper; set aside.
On four 8-inch or eight 4-inch skewers alternately thread ham, basil/spinach, mushrooms and bell pepper, folding ham and basil/spinach to fit on skewers.
Brush generously on all sides with oil and vinegar mixture. Grill until mushrooms are golden, turning occasionally, 6 to 7 minutes.
Place skewers on a serving platter, brush with any remaining oil-vinegar mixture. Serve over steamed rice sprinkled with chopped parsley, if desired