To prepare the pork and pineapple: In a cup, mix the sugar, cumin, coriander, cinnamon, pepper, and salt. Mix half of the spices with the pork, then toss with the oil. Mix the remaining spices with the pineapple. Let stand at room temperature for 15 minutes while preparing the avocado cream.
Whisk the avocado with the sour cream, lime/lemon juice, and salt in a small bowl. Press a piece of plastic wrap directly onto the surface to keep the cream fresh looking.
Coat a large nonstick pan with olive oil spray. Warm over medium-high heat for 2 minutes. Add the pork and cook, turning once or twice, for 8 minutes or until browned and cooked through. Add the coriander and toss to combine. Transfer to a clean plate and cover loosely to keep warm.
To assemble each serving, place 3 tortillas on a plate. Divide 1/4 of the pork and pineapple between each tortilla. Top with the cream and roll up.