Special equipment: a stand mixer with a paddle attachment and a pressure cooker
For the octopus: Combine the octopus and 1 cup salt in a stand mixer fitted with a paddle attachment. Turn the mixer to high and tenderize the octopus for 5 minutes.
Combine the chicken stock, onion, garlic, ginger, lemon, soy sauce, olive oil, sambal chile paste, crushed red pepper flakes, 1 cup water, 1/2 teaspoon salt and the pepper in a pressure cooker. Bring the mixture to a simmer. Remove the octopus from the stand mixer and rinse it well to remove the salt. Add the octopus to the pressure cooker, seal the lid and cook the octopus over medium heat until tender, 20 to 25 minutes.
For the sauce: Combine the oyster sauce, vinegar, garlic, ginger, sesame oil and sambal chili paste in a small saucepan and bring to a simmer. Remove from the heat.
Remove the octopus from the pressure cooker and discard the cooking liquid.
Heat a grill or grill pan over medium-high heat and oil the grates. Grill the octopus, brushing with the sauce and turning once, until charred, 2 to 3 minutes per side.
For the salad: Combine the vegetable oil, vinegar and sesame oil in a large bowl. Season with salt and pepper. Add the watercress, cabbage, pepper, cucumber, onion and lemon zest and toss to coat with the dressing. Divide the salad among 4 plates. Top each salad with a few pieces of the octopus.
This recipe was created by a contestant during a cooking competition. It has not been tested for home use.