In a skillet, cook the jalapenos in a little bit of oil until softened & charred. Transfer to a bowl, cover, & let cool slightly. Remove & discard the skin, stem, & seeds - and finely chop the chiles.
Fry the bacon until crispy & reserve 1 tablespoon of bacon fat.
In a large bowl, combine the reserved bacon fat, half of the chopped chiles, & crumbled bacon. Then mix in the ground beef. Form into 6 patties & season with salt & pepper.
In a medium bowl, combine the crumbled queso fresco, mayo, buttermilk, 1 tablespoon of olive oil, & the remaining chiles. Season with salt & pepper - refrigerate.
In another bowl, toss together the sliced avocados, onion, cilantro, & remaining tablespoon of olive oil. Set aside.
Grill the burgers, turning once, for about 10 minutes for medium rare - longer if you like them more well done. Just before the burgers are done, toast the buns on the grill (or skillet) for about a minute.
Place a burger on each bun bottom, top with some avocado salsa & queso fresco dressing - and finish with the top half of the bun.