In small pan, sauté (in olive oil) diced red pepper, celery, carrot and scallion until just softened. Take off heat and set aside to cool.
In medium size bowl, mix together mayo, lemon juice, chili paste, and seasonings. Add the veggies once they have come to room temp. Salt to taste if needed.
Add the cooked/drained pasta and fresh parsley. Mix together and chill in the refrigerator for a few hours.
I leave my cooked pasta in the strainer until I'm ready to add it to my mayo mixture; this gives it time to drain completely, becoming almost dry.