Prepare all of the ingredients. Preheat grill pan or griddle to medium.
In a large saute pan over medium-high heat, add 1 tbsp of avocado oil, onion, and garlic. Cook for 2 minutes then add beef, salt, cumin, and chili powder. Cook until no longer pink. Remove from heat.
Brush on side of each slice of bread with remaining avocado oil. Build the sandwiches: Slice of bread (with oil on outside), slice of pepperjack cheese, 3-4 dollops of beans (don't spread out), portion of beef, slice of colby jack cheese and another slice of bread (with oil on the outside). Slightly press down, not smush, to hold everything together. Repeat for remaining sandwiches.
Place sandwiches on grill pan or griddle. Cook for 5-7 minutes on each side, until cheese in melted and the bread is golden toasted. Cut each sandwich on the diagonal. Serve with a portion of Taqueria Salsa for dipping.