Heat the oven to 425°F. Line a large rimmed sheet pan with parchment paper for easier cleanup.

Put the trimmed green beans on a cutting board. If any are very long, cut them in half so they fit on the pan and are easier to serve.

Put the red onion wedges on a plate or small tray so they are ready to go. Keep the layers mostly attached so the wedges roast instead of falling apart.

Put the chicken thighs in a large bowl. Set the bowl aside while you make the sauce.

In a food processor or blender, add the roasted red peppers, almonds, garlic, red wine vinegar, smoked paprika, 3 tablespoons of the olive oil, 1/2 teaspoon of the salt, and 1/4 teaspoon of the black pepper.

Blend the mixture until it looks like a thick, slightly textured sauce. Stop and scrape down the sides once if needed so the almonds are fully broken up.

Scoop 1/2 cup of the sauce into a small bowl and set it aside for serving. Pour the remaining sauce over the chicken in the large bowl.

Turn the chicken in the bowl until each piece is coated with the sauce. Make sure the sauce is spread over the tops and sides of the thighs.

Put the red onion wedges on the lined sheet pan. Drizzle them with 1 tablespoon of the olive oil and sprinkle with 1/2 teaspoon of the salt.

Spread the onions into a single layer on one half of the sheet pan. Leave space on the other half for the chicken.

Lift the chicken thighs from the bowl and put them on the open side of the sheet pan. Let any thick coating stay on the chicken, but leave behind any loose puddles of sauce in the bowl.

Slide the sheet pan into the oven and roast for 15 minutes. The onions should start to soften and the chicken should lose its raw look on top.