In a large pot over low heat, cook jalapeño, serrano, chile güero, onion, garlic, and grapeseed oil until everything has softened, about 10 minutes. Remove from heat and allow to cool.
Place cooled vegetables into a blender, reserving oil. Blend on high and slowly stream in reserved oil to emulsify. Continue blending guacachile until smooth, and season with salt to taste.
Brush steaks, broccolini, and bok choy with olive oil. Season with salt and pepper.
On a gas or charcoal grill, place steaks over direct heat. (If cooking inside, set a cast-iron pan over medium-high heat until it’s smoking.) Cook until the steaks reach desired level of doneness: 2 minutes on each side for medium-rare, 3 minutes for medium.
Transfer steaks to a cutting board and sprinkle with more salt and a squeeze of lime. Allow to rest before slicing, about 3-5 minutes.
Serve with guacachile salsa, cilantro, lime wedges, and warm tortillas.