1. In a large jug, whisk together the ingredients for the marinade. Pour half of the marinade into a large shallow dish and reserve the other half for later as the dressing. Add the chicken fillets (either thighs or breasts) into the marinade and coat evenly. Allow the chicken to marinate for 15-30 minutes, or up to 2hours in the fridge for more flavour.
2. While the chicken marinates, prepare the salad ingredients. In a large salad bowl, combine the washed and dried Romaine lettuce, diced cucumber, diced Roma tomatoes, thinly shallots, and sliced avocado. Toss gently to combine.
3. Heat vegetable oil in a frying pan over medium heat to 160C. Toss the thinly sliced shallots in the plain flour, salt, and black pepper until well coated. Fry the shallots in the hot oil for 2-3 minutes, or until golden brown and crispy. Remove from the oil and place on a paper towel to drain any excess oil.
4. Heat 1 tablespoon of olive oil in a grill pan or on a grill plate over medium-high heat. Grill the chicken for 4-5 minutes on each side, or until browned and fully cooked through. You can check that the chicken is cooked by cutting into the thickest part – it should no longer be pink, and juices should run clear. Once cooked, allow the chicken to rest for 5 minutes before slicing into thin strips.
5. Arrange the sliced chicken over the salad. Drizzle with the reserved marinade dressing. Top with crispy shallots for a crunchy finish and serve with lemon wedges on the side.