Add whole octopus to a stock pot and cover with water. Simmer for 1 hour or until tender.
Spray barbeque grill with oil and heat. Remove the octopus from the water and place directly onto a hot grill. Cook for 10 minutes to heat through. Remove the octopus from the grill and chop into medium size pieces.
In a large bowl, combine the chopped octopus, tomatoes, onion, green onion,chili pepper, fish sauce, lime juice, ogo, canola oil, soy sauce, salt and pepper.
Pairs great with Squid Luau!