This dish can be served warm or cold, and can serve either as a salad or a side dish.
Bring a large pot of salted water to a boil.
Remove the leaves from 1 bunch of basil and toss in a food processor with 3 T. olive oil, 1 minced clove of garlic, and 3 T. toasted pinenuts or walnuts. Process until semi-smooth, then add salt to taste.
Core 2-3 sweet peppers and remove the seeds. Cut in very thin slices, then cut the slices in half.
Dice 2 Roma tomatoes and toss with the pesto.
Trim 1/2 lb. of green beans and cut them in halves to make 2-3 inch pieces. Parboil for 2 minutes or until they are tender but still quite crisp, then remove and rinse with cold water. Drain and toss with the pesto and peppers while they are still hot.
Allow to the beans to sit at least 10 minutes. Season with salt, pepper and lemon juice.