If lobster tails are frozen, thaw them completely. To hasten thawing, place lobster tails in a ziploc plastic bag, zipped tight. Then place bag of lobster tails in a large bowl and run cold water over it. Let sit for about 10 minutes, submerged in the water, and then drain and repeat the process two more times. Rinse tails lightly and pat dry with paper towels.
Butterfly the tails by cutting lengthwise through the centers of the hard top shells and about half-way through the top of the meat with a kitchen shears. With your fingers, press shell halves of tails apart. If you see a dark line running down the center of the meat, that is the digestive tract (it may already be completely removed or only partially removed). To fully remove it, simply grasp it with a paper towel, pull it out and discard.
Insert a metal skewer down the lobster tail so the tail stays straight and doesn’t curl up on the grill.
In a small bowl, stir butter and sriracha until well combined.
Heat grill to medium-high, about 475°.
Spread about 1 tablespoon of prepared sriracha butter over the meat of each lobster tail. Place tails on the grill, meat side down on the grates, for about 4 to 5 minutes. The lobster shell should turn bright orange in color.
Flip tails over and spoon another teaspoon of sriracha butter onto the meat of each tail. Grill for an additional 3 to 4 minutes, or just until lobster meat is opaque. Do not overcook or the lobster meat will be dry.
Remove tails from grill and let sit for a couple minutes before serving.
Sprinkle with fresh chives. Serve with fresh lemon wedges for squeezing over the tails and additional reserved sriracha butter.