Wash and dry the green beans.

Place green beans in a large bowl.

Add 1 tablespoon olive oil and half of the salt to the green beans.

Season with pepper to taste.

Toss to coat the green beans well.

Spread the green beans on a rimmed baking sheet.

Cut the red pepper and onion into slices.

Place the pepper and onion in a bowl.

Add the remaining olive oil and salt to the pepper and onion.

Season with pepper.

Toss to coat the pepper and onion well.

Spread the pepper and onion on a second rimmed baking sheet.

Heat the oven to 475 degrees.

Toast the walnuts in a small baking dish for 5 to 10 minutes, watching carefully.

Cool the walnuts, then coarsely chop.

Roast the vegetables until they're soft and starting to caramelize, 15 to 30 minutes, stirring and turning every 5 minutes.

Transfer to a shallow serving dish.

Sprinkle with the walnuts.

Crumble the blue cheese over the vegetables.

Sprinkle with the chives.

Serve warm or at room temperature.