Put the lemon juice in a small saucepan and bring to a boil over high heat. Cook until reduced to 1/4 cup. Stir in the honey. Let cool.
Add the butter and zest to the reduced lemon juice and mix until smooth.Season with salt and pepper.
Bring a large pot of salted water to a boil. Add the lobster tails and boil for 4 minutes.
Split each lobster tail lengthwise down the underside with a heavy knife.
Preheat the grill to medium heat.
Brush the lobster flesh with oil and sprinkle with salt and pepper.
Place the tails flesh-side down on the grill and grill until slightly charred, about 3 minutes. Brush with the prepared sauce and grill 2 more minutes.
Remove from the grill to a platter, flesh-side up. Serve with some cilantro leaves and lemon zest.