For the Guacamole, mix all ingredients in medium bowl until well blended. Cover surface with plastic wrap. Refrigerate while preparing burgers.
For the Burgers, bring stock and chipotle pepper to boil in small saucepan. Stir in quinoa. Reduce heat to low; cover and simmer 12 to 15 minutes or until quinoa is tender.
Place quinoa and beans in food processor; cover. Process until coarsely chopped. Add remaining ingredients except oil; process until well blended. Form mixture into 4 patties. Refrigerate 1 hour.
Heat oil in large, nonstick skillet on medium-high heat. Add patties; cook 4 to 6 minutes per side or until patties are heated through and crisp. Serve with Guacamole on whole grain hamburger rolls topped with red onion slices, if desired.