1/3 cup plus 2 tablespoons vegetable or canola oil, divided
3 tablespoons white wine vinegar
2 tablespoons lime juice
3 red onions, one finely chopped and two sliced, divided
1 garlic clove, minced
1 teaspoon hot sauce
1/2 teaspoon Kosher salt
3 red bell peppers, sliced
16–20 flour tortillas, warmed
Shredded sheddar cheese or crumbled queso fresco
In a large bowl, combine 1/3 cup vegetable oil, vinegar, lime juice, minced onion, garlic, hot sauce, salt, and pepper. Add chicken, stir to coat, and marinate in refrigerator for at least 6 to 8 hours, but preferably overnight.
Preheat oven to 400°F. Place peppers and sliced onions on a sheet pan and drizzle with remaining 2 tablespoons oil. Season with Kosher salt. Place marinated chicken on top of the vegetables and roast in oven until chicken is just cooked through, about 20 to 30 minutes. Remove from oven and slice chicken.
Top warmed tortillas with chicken, pepper and onions, guacamole, cheese, a squeeze of lime, and cilantro. Devour immediately.