Cut ham into 1/4 inch strips, about 1 1/2 inches long. Cut each tomato into 8 wedges; cut pepper into 1/2 inch wide strips and onion into thin lengthwise slivers. Cut squashes into 1/4 inch wide slices, halving lengthwise if larger than 1 inch in diameter.
In wok or large skillet over medium high heat, cook ham and all vegetables, except tomatoes, in hot oil about 5 minutes, stirring frequently. Reduce heat to medium. Add remaining ingredients, except tomatoes; stir and cook until vegetables are crisp-tender, about 10 minutes. Add tomato wedges and continue cooking until tomatoes are heated through.
Good served with brown or white rice.
Serves 4