Drain chickpeas, reserving 1/4 cup of the liquid. Place chickpeas, tahini, lemon juice, garlic, cumin, salt and red pepper in food processor; cover. Process until smooth, scraping down sides as necessary. Add reserved liquid; process until smooth. Store in airtight container in refrigerator up to 2 days.
To serve, drizzle hummus with olive oil and garnish with chopped green onions, chopped olives or chopped tomato, if desired. Serve with warm pita wedges or pita chips.