Prepare a gas grill for direct-heat cooking over medium heat; (see Grilling Procedure after recipe if needed)

Gently mix pork, chipotle, garlic, and a scant tsp salt until just combined. Form into 4 (1/2-inch-thick) patties.

Oil grill rack, then grill patties, covered, 4 minutes.

Flip patties and top with a slice of cheese. Grill, covered, until just cooked through, 1 to 2 minutes more.

Spread buns with mayonnaise and assemble burgers with tomatillo, avocado, and cilantro.

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~GRILLING PROCEDURE~

Charcoal Grilling Instructions for Direct-Heat Cooking:

Open vents on bottom of grill. Light a large chimney starter full of charcoal (preferably hardwood). When coals are lit, dump them out across bottom rack, leaving a space free of coals on one side of grill equal to the size of the food to be grilled where food can be moved in case of any flare-ups. When charcoal turns grayish white (start checking coals after 15 minutes), the grill will be at its hottest and will then begin to cool off. How long you can hold your hand 5 inches above the grill rack directly over the coals determines the heat of your grill, as follows:

Hot: 1 to 2 seconds

Medium-Hot: 3 to 4 seconds

Low: 5 to 6 seconds

Gas Grill Instructions:

Preheat burners on high, covered, 10 minutes, then, if necessary, reduce to heat specified in recipe.

Charcoal Grilling Instructions for Indirect-Heat Cooking:

Open vents on bottom and lid of grill. Light a large chimney starter full of charcoal (preferably hardwood). When coals are lit, dump them out along two opposite sides of bottom rack, leaving a space free of charcoal in middle of rack equal to the size of food to be grilled. When charcoal turns grayish white (start checking coals after 15 minutes), the grill will be at its hottest and will then begin to cool off. How long you can hold your hand 5 inches above the grill rack directly over the coals determines the heat of your grill (see above for times).

Gas Grill Instructions:

Preheat all burners on high, covered, 10 minutes, then adjust heat according to recipe. Just before grilling, turn off 1 burner (middle burner if there are 3).