Slice the breasts into strips about 2 cm wide, cutting on a slight diagonal so they thread into flat ribbons.
Mix the soy sauce, fish sauce, brown sugar, curry powder, turmeric, garlic, lemongrass, and coconut milk. Toss the chicken in it and refrigerate for 1 hour, or 20 minutes if that is what you have.
Thread the strips onto soaked skewers in a flat ribbon, weaving the skewer through each strip two or three times. Flat skewers cook evenly; bunched ones do not.
Make the sauce: whisk the peanut butter, lime juice, soy sauce, honey, and sambal with hot water, 1 tablespoon at a time, until it pours slowly off a spoon. About 4 tablespoons usually does it.
Heat a grill or grill pan until properly hot. Cook the skewers 2 to 3 minutes per side, until charred in spots and just cooked through. Thin strips overcook fast, so stay close.
Rest 2 minutes and serve with the peanut sauce, cucumber chunks, and raw red onion.