Halve the butternut squash lengthwise, remove seeds, and place it in a microwave-safe dish, cut side down.
Microwave, covered, on high until soft, for about 15-20 minutes; cool slightly.
Meanwhile, in a saucepan, combine pineapple salsa and black beans; heat through over medium heat, stirring occasionally.
Scoop out the cooked squash pulp and place it in a mixing bowl.
Mash until smooth; stir in salt, ground cumin, and ground chipotle pepper.
Spoon the squash and salsa mixture onto the center of warmed tortillas, top with fresh baby spinach, and roll up.