Combine the flour, cumin, chipotle, and salt together in a medium bowl. Whisk in the seltzer water to make a batter.
Season the shrimp with salt.
In a heavy, wide skillet or casserole, pour oil to a depth of 4 inches and heat over medium for at least 5 minutes. Test the heat by dipping a wooden spoon or the tip of a piece of shrimp into the oil — it should bubble happily around whatever you introduce into it. Set a cooling rack on a baking sheet and cover the rack with paper towels. If you don’t have a cooling rack, just cover the baking sheet with paper towels.
Dip the shrimp into the batter and carefully drop into the hot oil. Fry until golden and crisp, turning once, about 2-3 minutes. Transfer to the cooling rack and season with salt.
Serve the shrimp on a warm tortilla topped with the slaw and guacamole salsa.