2 teaspoons tamarind paste (buy at your Asian store)
3 teaspoons whole coriander seeds
3 shallots, peeled and coarsely chopped (about 2.5 ounces total)
2 cloves garlic, peeled and coarsely chopped
1 teaspoon ground turmeric
1 piece fresh ginger, 1/2 inch long, peeled and coarsely chopped (about 1 tablespoon)
2 teaspoons dark brown sugar
1 teaspoon peanut oil, plus more for the grill
1/2-3/4 teaspoon salt
1 pound boneless skinless chicken (thigh or breast meat) cut into 1/2 strips
20 sharp, thin, 10-inch-long bamboo skewers, soaked in water for at least 30 minutes and drained
TO MAKE the marinade, place the tamarind paste in a small nonreactive bowl. Place the coriander seeds in a small food processor. Pulse until the coriander is well ground and dusty, about 2 minutes. (Don’t remove the coriander from the food processor at this point—you’re going to grind it again along with the other flavoring-paste ingredients.)
ADD the tamarind paste, shallots, garlic, turmeric, ginger, sugar, oil and salt to the food processor. Pulse until you have a smooth paste, the consistency of creamy mashed potatoes. (If the paste does not purée properly and repeatedly creeps up the side of the food processor instead of grinding, add up to 2 tablespoons of water; 1 tablespoon at a time, periodically turning the processor off and, with a spoon, scraping the unground portions down toward the blade as you go.) Transfer the blended marinade into a nonreactive bowl large enough to hold the chicken.
SLICE the chicken into long, 1/4-inch thick strips. The pieces should be no wider than 1 inch.
ADD the sliced chicken to the bowl, and combine it well with the marinade, making sure that every piece is coated. Allow the chicken to marinate refrigerated for 1 to 2 hours (or overnight).
THREAD the chicken strips onto the presoaked bamboo skewers, weaving the point of each skewer through the center of the chicken every 1/4 inch to make sure it holds tight and remains secure while it cooks. Use 1 to 4 pieces of chicken per skewer, depending on how long the pieces are, making sure that the chicken extends from the tip to the middle of the skewer. Leave plenty of room so you can grab the skewer at the bottom—the meat should not extend from one end to the other.
TO COOK on a grill, first prepare a medium-hot wood charcoal fire, and oil the grill rack liberally. When the fire is hot (this may take up to 20 minutes), place each skewer on the grill, making sure that the chicken, not the skewer, is directly over the heat. Grill the chicken until it is cooked through and has begun to pick up a few crispy brown-black spots, about 2 to 5 minutes (depending on how hot the fire is). Turn the skewers over carefully and continue grilling until the other side is browned, another 2 to 5 minutes. Do not overcook the meat—it will dry out. Test a piece by touching it with your finger. The chicken should be firm, not squishy.
TRANSFER to a serving dish and let the skewers rest for about 1 minute, until they are cool enough to handle. Serve immediately.