Peel and devein shrimp, leaving tails intact. Combine 2 tablespoons tequila and lime juice in a glass bowl; add shrimp, and toss well. Cover and chill 20 minutes.
Combine remaining 1 tablespoon tequila, mayonnaise, and next 8 ingredients; stir well, and set mixture aside.
Remove shrimp from marinade; discard marinade. Coat a large nonstick skillet with cooking spray; add peanut oil. Place over medium-high heat until hot. Add shrimp, and saute 2 minutes or until shrimp turn pink.
To serve, arrange shrimp evenly on toasted bread slices; top each with 1 1/2 tablespoons mayonnaise mixture. Serve immediately.