Grind the lime leaves, galangal, lemongrass, turmeric, shallots, garlic, chilies, and cilantro in a food processor into a coarse paste.
Heat the oil in a saucepan over medium-high heat. Cook the spice mixture for 5 minutes, stirring frequently, until there is a fragrant aroma. Set aside to cool a bit.
In a large bowl, mix the ground beef, flour, and rub until well mixed. Add the cooled spice paste and mix thoroughly.
Clean the lemongrass skewers by removing any gunk or hard outer layers. Trim the tips so it looks like a nice skewer. Wash.
Mound the ground beef mixture over the stalk area of the lemongrass into a 4-inch (10cm) sausage shape. Leave 1 inch (2.5cm) of the bottom stalk exposed. Repeat until the meat mixture is used. The sausage can be sausage-shaped thick or thin, adjust the cooking time based on thickness.
Chill the skewers for 30 minutes or more so they will hold together when you grill them.
Set up the grill with a medium-hot zone and a cool zone.
Grill over the medium-hot side until beef is cooked, turning often, about 8 minutes. It helps if you brush/baste it with a bit of oil. If there is a flare-up, move your skewers to the cool zone or spritz with a spray bottle of water.
Serve it with BBQ sauce spiked with some Sriracha hot sauce and sesame seeds.