Using a toothpick or fork, poke several small holes in each grape.
Place the grapes in an airtight container and pour the tequila on top. If the grapes aren't completely covered, add more tequila.
Cover and chill in the refrigerator for 4 to 24 hours.
Strain the tequila and store it in an airtight jar to use in drinks or recipes.
Add the grapes back to the container and toss with chamoy and chili lime seasoning.
Add 4-6 prepared grapes to each wooden skewer, then top with extra chamoy or seasoning before serving.
Notes
Storing: These are best within 24 hours of coating them, since the chamoy starts to slide off after that. For longer, freeze them in a single layer for 1 to 2 hours until solid, then move them to a freezer bag for up to 3 months and eat them straight from frozen.
Save the strained tequila. It picks up a little sweetness from the grapes and it's still good for margaritas or a marinade.
If your grapes taste too sour, add a tablespoon of agave or honey when you toss them with the chamoy and Tajín. Red grapes are a sweeter option than green if you'd rather start there.
Swapping the tequila changes the flavor more than you'd think. Reposado and añejo are warmer and oakier, and mezcal brings smoke.