Peel, trim, and cut carrots into ¼" diagonal slices. Trim ends off green beans. Cut roasted red pepper into ½" dice. Mince garlic. Stem and coarsely chop oregano. Stem and coarsely chop mint. Stem, seed, and mince Fresno chile. Keep some or all seeds if you prefer more spice. Rinse chicken breasts, pat dry, and season both sides with ¼ tsp. salt and a pinch of pepper. On a separate cutting board, use a fork to pierce chicken 10-12 times per side. This will tenderize the meat and allow marinade to penetrate.
Marinade Chicken and Make Piri-Piri Sauce
Place chicken breasts in a medium mixing bowl with half the Fresno chile, half the oregano, half the paprika, and 1 Tbsp. olive oil. Season with ¼ tsp. salt and a pinch of **pepper and toss to coat. Allow chicken to marinade 15 minutes. In a second medium mixing bowl, combine roasted red peppers, remaining Fresno chile and seeds (to taste), remaining oregano, half the garlic, remaining paprika, and 2 Tbsp. olive oil. Season with ½ tsp. salt and ¼ tsp. pepper and stir to combine.
Roast the Carrots
Place carrots on one side of prepared baking sheet. Drizzle with 1 tsp. olive oil and season with ¼ tsp. salt and a pinch of pepper. Toss to coat and spread into asingle layer. Roast until slightly softened, 8 minutes. Remove from oven. Carrots will finish cooking in later step.
Cook the Green Beans
Add green beans and remaining garlic to baking sheet. Drizzle with ½ tsp. olive oil. Bake until vegetables are tender and slightly caramelized, 8-10 minutes. Remove from oven and carefully combine vegetables with mint. While vegetables roast, cook chicken.
Cook the Chicken
Heat an outdoor grill or grill pan prepared with cooking spray over medium heat. Remove chicken from marinade and shake off any excess. Add chicken to hot grill and cook until browned and chicken reaches minimum internal temperature of 165 degrees, 5-6 minutes per side. Remove and rest 3-5 minutes.
Plate the Dish
Serve roasted vegetables on a plate alongside chicken. Top with piri-piri sauce.