In a medium bowl, mash the avocados. Add in the Greek yogurt, jalapeño, red onion, cilantro and 1 1/2 tablespoons of the lime juice and mix to combine. Season the guacamole with salt and pepper and press a piece of plastic wrap directly onto the surface of the guacamole. You may also prepare the lime guacamole in a food processor. Set aside.
In another bowl, toss the cabbage with the 2 tablespoons of olive oil and 1 1/2 tablespoons of lime juice. Season with salt and pepper. Set aside.
Rinse and paper towel dry the shrimp. Brush with oil and season with salt and pepper. Grill over moderately high heat until lightly charred and cooked through, about 3 minutes on each side. Transfer the shrimp to a platter.
If you have a gas stove, warm each tortilla directly over the open flame set on low. Watch as to not burn. Use tongs to flip to other side and to remove. Or, warm the tortilla in a hot skillet about 2-3 minutes each side. Place each warmed tortilla under a tent of tin foil or place in a warm oven.
To assemble each taco, spread a dollop of guacamole on a tortilla. Top with several pieces of shrimp, a few tomato slices and a large spoonful of the cabbage slaw. Serve with the lime wedges.