Combine rice, meat and beans with spices and grill seasoning. Form 4 big patties from the meat and bean mixture then heat 1 tablespoon oil, a turn of the pan, in a large skillet over medium-high heat. Cook patties 7 to 8 minutes on each side.
While burgers cook, combine avocado with garlic, lime zest and juice, jalapeno and red onion. Mash to roughly combine, then stir in the sour cream.
Place burgers on buns with lettuce and tomato and top with sour cream guacamole.