Stir together water and sugar in a large saucepan. Bring to a boil over high heat, and cook to a soft ball stage, about 20 minutes (when a drop of syrup is put into cold water it forms a small ball). Remove from heat and cool.
Combine the red pepper, garlic, hot pepper paste, and salt in the bowl of a food processor. Blend until the red peppers are pureed. You will still be able to see the seeds. Add the puree, lemon juice, vinegar and oyster sauce to the cooled syrup and stir well.
For Flank Steak:
Preheat oven to 450 degrees (230 Celsius). Place flank steak on baking sheet. Spread with oyster sauce and sprinkle with pepper. Bake for 25 minutes or until medium rare. Rest 15 minutes. Slice thinly against the grain.
Heat oil over medium heat in a small skillet, and cook garlic just until it is fragrant and begins to brown, about 1 minute. Remove from the heat and cool completely. In a large bowl, toss cooled pasta with garlic and oil.
Add red pepper, green onion, cilantro, mint and sliced flank steak. Toss with enough dressing to coat and chill before serving.