Place the chicken, garlic, lime juice, sofrito, adobo, sazón, salt, and oregano. Combine and set aside.
Place the chicken and marinade in a pot over low to medium heat. Cover and cook for 10 minutes per side, until the chicken is partially cooked. Remove from the pot, pat the chicken dry with paper towels to help it crisp up and prevent the oil from popping, and set aside for the next step.
Add frying oil to a pan over low to medium heat and let the oil get hot before carefully placing the chicken into the oil. Cook until golden brown on both sides, or about 5 minutes.
Remove chicken from the oil and place on a paper towel lined plate. Serve with tostones and pickled onion. Buen provecho!