To make dressing, combine oil, vinegar, mustard, garlic and lemon juice and season to taste with salt and pepper. To make salad, cook pasta in boiling salted water until al dente. Drain and cool. Place in large bowl. Heat olive oil in skillet. Add green and red peppers and saute until barely tender. Add to pasta along with dill. Add dressing. Toss to coat pasta well. Chill, covered, until serving time.