In a large nonstick skillet, heat 2 tsp. EVOO over medium-high. Add peppers, onion and 1/4 tsp. salt. Cook until peppers are tender, about 10 minutes. Stir in 1 tsp. vinegar. Spread pepper mixture in a 9-inch pie pan coated with cooking spray; sprinkle with cheese. In a medium bowl, whisk eggs, half-and-half, oregano and 3/4 tsp. salt. Pour into the pie pan. Bake at 400 degrees until set, about 30 minutes. In a bowl, whisk remaining EVOO and vinegar; toss with greens. Serve quiche with greens.