Make the poke: Mix the tuna, onion, cucumber and jalapeño in a large bowl.
Puree the soy sauce, vinegar, ginger, sambal, sesame oil and brown sugar in a blender, scraping down the sides, 1 minute. Add to the tuna; toss. Refrigerate 15 minutes.
Meanwhile, make the wonton chips: Heat 2 inches of vegetable oil in a Dutch oven until a deep-fry thermometer registers 350 degrees F. Working in batches, fry the wonton wrappers until golden, about 2 minutes. Drain on paper towels; sprinkle with salt.
Divide the poke among glasses or bowls. Top with the scallions and wonton chips.