With a zester or vegetable peeler, cut the zest from the orange in very narrow strips, being careful to avoid any of the white pith. Bring a saucepan of water to boil. Place the strips in a small sieve or slotted spoon, plunge them into the boiling water, remove immediately, and rinse under running cold water. Repeat three times to remove the bitter taste. Pat the orange strips dry with paper towels.

In a frying pan over medium heat, melt the butter. Add the onion and sauté until translucent, 3-4 minutes.Add the garlic and shrimp and cook, stirring frequently, until the shrimp turn pink and begin to curl, 4-5 minutes. Do not overcook the shrimp; they should be tender, not rubbery.

Add the chiles and orange strips. Stir briefly to mix. Pour the tequila over the shrimp, carefully ignite with a long match, and let the flames burn out. Add the minced cilantro, season with salt, and serve on a warmed platter or plates.