Combine lemon juice, salt, garlic powder, ginger powder, and sugar. Mix well.
Place the cubed ahi tuna in a large bowl. Pour-in the lemon mixture and gently toss until all the ingredients are well blended.
Add the chopped chili and ground black pepper. Gently toss. Cover and place inside the fridge for at least 1 hour.
Serve chilled. Share and enjoy!