If using meat that has not been ground: To hand-chop the meat, thinly slice it, then place the slices on a large cutting board. Holding a cleaver in each hand, chop the meat with alternating hands, chopping across the piled meat one way, then another, and repeating until finely chopped. Sprinkle on the turmeric and set aside in a large bowl. Alternatively, to use a food processor, cut the meat into 5 or 6 pieces and place in the freezer for 20 minutes. Transfer the meat to the processor, add the turmeric, and pulse to finely chop. Transfer to a large bowl and set aside.
If using ground meat: Place in a bowl, sprinkle with the turmeric, and set aside.
To make and cook the sliders, combine the lemongrass, garlic, shallots, ginger, and salt in a large mortar or the food processor and pound or pulse to a coarse paste. Add the rice, chile powder, and tomatoes and pound or pulse again.
Add the flavor paste to the meat and knead it thoroughly into the meat. Shape the mixture into balls about 1 inch in diameter, then flatten each one gently into a thick patty. Set aside on a lightly oiled plate.
Place a large skillet over high heat. Add the oil, then lower the heat to medium-high and add the sliders, being careful not to splash yourself with oil; arrange the first ones around the edges of the skillet and work your way in to the center. Cook for 3 minutes or so, then use a wide metal spatula to turn the sliders over. As the meat starts to release water, raise the heat a little to evaporate it. Remove the sliders from the pan when they are firm to the touch or have reached the degree of doneness you like.