Step 1Make the spring onion salsa verde: Rinse and dry the spring onions. Peel off any dried or brown outer layers from the white parts then trim off only the dried, woody tips from the greens. Thinly slice the white and green parts from the onions and reserve a small handful of each in a small bowl for garnishing the finished dish.
Step 2Place the rest of the sliced spring onions into a blender or food processor, along with the cilantro, wine, 3/4 teaspoon salt, 1/2 teaspoon pepper, garlic and serrano and blend until very smooth, about 30 seconds.
Step 3Heat the oven to 425 degrees.
Step 4Season the chicken thighs all over with salt and pepper. Place the thighs, skin side down, in a large ovenproof skillet wide enough to fit them in a single layer, then place the skillet over medium-high heat. Once the skins start sizzling, continue cooking the thighs, undisturbed, until well-browned, 6 to 8 minutes. Flip the thighs, skin side up, onto a plate and pour off the fat in the skillet (or save for another use). Pour the spring onion salsa verde into the pan and bring the salsa to a boil. Return the thighs to the skillet, skin side up, then place in the oven and braise until the chicken is cooked through, the skin is crisp and the salsa is slightly reduced, about 25 minutes.
Step 5Remove the skillet from the oven and sprinkle the chicken and salsa with the queso fresco and the reserved spring onions. Serve with avocado and lime wedges and with bread, tortillas or rice.