In a bowl or resealable bag, combine coconut milk, red curry paste, minced garlic, and dark soy sauce to create the marinade. Add the chicken, ensuring they are fully coated. Marinate for at least 30 minutes, or overnight for deeper flavor.

In a medium bowl, whisk together peanut butter, rice vinegar, lime juice, honey, and sriracha until smooth. Taste and adjust spice level if desired. Chill the peanut sauce.

Preheat oven to 400°F (200°C). Line a large baking sheet with parchment paper or grease it with olive oil.

In a large bowl, combine chopped bell peppers, broccoli, and sliced onion. Drizzle with olive oil and season with salt and pepper. Toss until coated.

Spread marinated chicken in the center of the baking sheet and arrange vegetables around in a single layer.

Bake in the oven for about 30 minutes, until chicken reaches 165°F and vegetables are tender.

Remove from oven, drizzle peanut sauce over chicken and vegetables. Garnish with green onions, cilantro, and sesame seeds. Serve with jasmine rice or rice noodles.