Bring 4 cups water to a boil in a medium saucepan. Cook the beans in boiling water for 5 minutes or until crisp-tender. Drain and rinse with cold water; drain.
Combine tomato and next 4 ingredients (through pepper) in a bowl. Divide beans evenly among 8 plates. Top each serving with 1/4 cup tomato mixture. Sprinkle each serving with 1 tablespoon sliced basil and 1 tablespoon cheese.
Made this tonight to go with grilled steaks. It was really tasty and I would make it again. I just had green beans, no wax beans and they were perfect after being blanched. I chopped grape tomatoes into eighths for the dressing, which ensured there was some tomato for every bute of bean :) this tastes like summer and I would happily serve this pretty salad to guests.
This was very very good, but I think I might change out the vinegar next time to balsalmic. I wanted a little bit more flavor, but then sherry vinegar pickings around here were very slim, so I think perhaps I didn't have a good one. I also thought it needed a little more salt, but that could be because I used goat cheese instead of feta (which is rather salty). All in all, I would make again. Very quick and easy and versatile.