For the marinade, place onions, cilantro, garlic, jalapeno, beer, juice, ¼ cup (60ml) oil, zest, salt and pepper in a blender and blend until smooth. Reserve ¼ cup (60ml) marinade and pour remainder into a large resealable bag. Add chicken and seal, removing as much air as possible. Turn to coat evenly. Place on a plate or in a bowl. Refrigerate for 20 minutes to 2 hours.
Heat oven to 375F (190C).
Remove chicken from marinade and dab with paper towels. Place chicken skin side up on a plate and season with salt and pepper. Heat half the remaining oil in a large non-stick pan over medium-high heat. Add half the chicken and cook until golden brown on both sides, 7 to 10 minutes. Transfer to a rimmed baking sheet and continue with remaining oil and chicken.
Transfer baking sheet to oven and continue to cook chicken until the internal temperature reaches 165F (74C), about 15 minutes.