Preheat grill to medium-high heat.
Combine ground beef, salsa, cilantro, cumn, chili powder, garlic powder, salt, cayenne pepper, and pepper in a large mixing bowl. Be careful not to overwork the beef. Form into 6 uniform patties, taking into account the shape of the sesame buns.
Slice the peppers into 6 equal portions. You want the portions to be wide enough to cover the burger patty.
Brush olive oil on both sides of the peppers. Sprinkle with salt.
Move the patties, the peppers, the buns, and the cheese slices out to the grill. Grill the burgers until the inside reaches 165 degrees Fahrenheit. At medium-high direct heat, this should take about 12 minutes. Flip the burgers after 6 minutes.
Add the peppers to the grill on indirect heat and cook simultaneously with the patties. If you prefer blistered peppers, place directly over flame until adequate blistering appears.
In the final 2 minutes of cooking the burgers, place the separated buns on the grill inside-down on indirect heat. Place the slices of cheese atop your patties.
Remove the buns, burgers, and peppers from the grill.
Assemble the burgers. Smear a 1/2 cup of guacamole on both the top and bottom inside bun of the burgers. Place a cheesy patty on the bottom bun. Follow up with a red pepper square atop the patty. Add the butter lettuce. Top with the bun.