In a blender or food processor, combine garlic, chili powder, paprika, chipotle chiles, pineapple juice, vinegar, and 1 cup pineapple chunks. Blend until smooth and set aside.
Heat olive oil in a large skillet over medium-high heat.
Add cauliflower florets and sliced onions to the skillet. Season with salt and pepper.
Cook for 12-15 minutes, stirring occasionally, until cauliflower is tender and onions are caramelized.
Reduce heat to low and stir in the pineapple sauce, remaining cup of pineapple chunks, and diced jalapeño.
Simmer for 8-10 minutes until sauce has reduced and coats the cauliflower. Some sauce should remain in the pan.
Remove from heat and stir in chopped cilantro.
Divide cauliflower mixture among warmed tortillas and drizzle with remaining sauce from the pan.
Top each taco with crumbled feta cheese, additional cilantro, and a squeeze of lime juice.