In a small bowl combine the lemon juice and zest, chopped herbs, garlic, crushed red pepper, and 1/2 cup of olive oil. Whisk to combine.
Place the chicken thighs in a wide flat dish so they are in a single layer. Add the herb mixture. Massage the thighs to coat with the herb mixture. Cover and refrigerate overnight. Note: If doing a quick marinade, leave the chicken out of the fridge for up to 1 hour.
Preheat grill. Brush and oil the grill to clean.
Remove the chicken from the marinade and brush off any excess herbs and oil. Season the chicken generously with salt and drizzle with a little bit of fresh olive oil.
Cut the 2 whole lemons in half and cut the tips off the ends; this will allow the lemons to stand up without rolling around. Place the chicken, skin side down, on the preheated grill. Place the lemons, flesh side down, on the preheated grill. Grill the chicken for 3 to 4 minutes and then rotate the chicken 90 degrees to create the lovely crosshatch pattern. Grill the chicken for another 3 to 4 minutes. Turn the chicken over and grill for another 4 to 5 minutes. Check for doneness (the chicken should be well cooked). Check the lemon halves to see if they are beautifully caramelized. Turn over to grill on the bottom for 2 to 3 minutes.